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December 20, 2023

Ivanti Sentry Vulnerability | Analysis & Insights

Darktrace observed a critical vulnerability in Ivanti Sentry's cybersecurity. Learn how this almost become a huge threat and how we stopped it in its tracks.
Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Sam Lister
Specialist Security Researcher
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20
Dec 2023

In an increasingly interconnected digital landscape, the prevalence of critical vulnerabilities in internet-facing systems stands as an open invitation to malicious actors. These vulnerabilities serve as a near limitless resource, granting attackers a continually array of entry points into targeted networks.

In the final week of August 2023, Darktrace observed malicious actors validating exploits for one such critical vulnerability, likely the critical RCE vulnerability, CVE-2023-38035, on Ivanti Sentry servers within multiple customer networks. Shortly after these successful tests were carried out, malicious actors were seen delivering crypto-mining and reconnaissance tools onto vulnerable Ivanti Sentry servers.

Fortunately, Darktrace DETECT™ was able to identify this post-exploitation activity on the compromised servers at the earliest possible stage, allowing the customer security teams to take action against affected devices. In environments where Darktrace RESPOND™ was enabled in autonomous response mode, Darktrace was further able inhibit the identified post-exploitation activity and stop malicious actors from progressing towards their end goals.

Exploitation of Vulnerabilities in Ivanti Products

The software provider, Ivanti, offers a variety of widely used endpoint management, service management, and security solutions. In July and August 2023, the Norwegian cybersecurity company, Mnemonic, disclosed three vulnerabilities in Ivanti products [1]/[2]/[3]; two in Ivanti's endpoint management solution, Ivanti Endpoint Manager Mobile (EPMM) (formerly called 'MobileIron Core'), and one in Ivanti’s security gateway solution, Ivanti Sentry (formerly called 'MobileIron Sentry'):

CVE-2023-35078

  • CVSS Score: 10.0
  • Affected Product: Ivanti EPMM
  • Details from Ivanti: [4]/[5]/[6]
  • Vulnerability type: Authentication bypass

CVE-2023-35081

  • CVSS Score: 7.2
  • Affected Product: Ivanti EPMM
  • Details from Ivanti: [7]/[8]/[9]
  • Vulnerability type: Directory traversal

CVE-2023-38035

  • CVSS Score:
  • Affected Product: Ivanti Sentry
  • Details from Ivanti: [10]/[11]/[12]
  • Vulnerability type: Authentication bypass

At the beginning of August 2023, the Cybersecurity and Infrastructure Security Agency (CISA) and the Norwegian National Cyber Security Centre (NCSC-NO) provided details of advanced persistent threat (APT) activity targeting EPMM systems within Norwegian private sector and government networks via exploitation of CVE-2023-35078 combined with suspected exploitation of CVE-2023-35081.

In an article published in August 2023 [12], Ivanti disclosed that a very limited number of their customers had been subjected to exploitation of the Ivanti Sentry vulnerability, CVE-2023-38035, and on the August 22, 2023, CISA added the Ivanti Sentry vulnerability, CVE-2023-38035 to its ‘Known Exploited Vulnerabilities Catalogue’.  CVE-2023-38035 is a critical authentication bypass vulnerability affecting the System Manager Portal of Ivanti Sentry systems. The System Manager Portal, which is accessible by default on port 8433, is used for administration of the Ivanti Sentry system. Through exploitation of CVE-2023-38035, an unauthenticated actor with access to the System Manager Portal can achieve Remote Code Execution (RCE) on the underlying Ivanti Sentry system.

Observed Exploitation of CVE-2023-38035

On August 24, Darktrace observed Ivanti Sentry servers within several customer networks receiving successful SSL connections over port 8433 from the external endpoint, 34.77.65[.]112. The usage of port 8433 indicates that the System Manager Portal was accessed over the connections. Immediately after receiving these successful connections, Ivanti Sentry servers made GET requests over port 4444 to 34.77.65[.]112. The unusual string ‘Wget/1.14 (linux-gnu)’ appeared in the User-Agent headers of these requests, indicating that the command-line utility, wget, was abused to initiate the requests.

Figure 1: Event Log data for an Ivanti Sentry system showing the device breaching a range of DETECT models after contacting 34.77.65[.]112.The suspicious behavior highlighted by DETECT was subsequently investigated by Darktrace’s Cyber AI Analyst™, which was able to weave together these separate behaviors into single incidents representing the whole attack chain.

Figure 2: AI Analyst Incident representing a chain of suspicious activities from an Ivanti Sentry server.

In cases where Darktrace RESPOND was enabled in autonomous response mode, RESPOND was able to automatically enforce the Ivanti Sentry server’s normal pattern of life, thus blocking further exploit testing.

Figure 3: Event Log for an Ivanti Sentry server showing the device receiving a RESPOND action immediately after trying to 34.77.65[.]112.

The GET requests to 34.77.65[.]112 were responded to with the following HTML document:

Figure 4: Snapshot of the HTML document returned by 34.77.65[.]112.

None of the links within this HTML document were functional. Furthermore, the devices’ downloads of these HTML documents do not appear to have elicited further malicious activities. These facts suggest that the observed 34.77.65[.]112 activities were representative of a malicious actor validating exploits (likely for CVE-2023-38035) on Ivanti Sentry systems.

Over the next 24 hours, these Ivanti Sentry systems received successful SSL connections over port 8433 from a variety of suspicious external endpoints, such as 122.161.66[.]161. These connections resulted in Ivanti Sentry systems making HTTP GET requests to subdomains of ‘oast[.]site’ and ‘oast[.]live’. Strings containing ‘curl’ appeared in the User-Agent headers of these requests, indicating that the command-line utility, cURL, was abused to initiate the requests.

These ‘oast[.]site’ and ‘oast[.]live’ domains are used by the out-of-band application security testing (OAST) service, Interactsh. Malicious actors are known to abuse this service to carry out out-of-band (OOB) exploit testing. It, therefore, seems likely that these activities were also representative of a malicious actor validating exploits for CVE-2023-38035 on Ivanti Sentry systems.

Figure 5: Event Log for Ivanti Sentry system showing the device contacting an 'oast[.]site' endpoint after receiving connections from the suspicious, external endpoint 122.161.66[.]161.

The actors seen validating exploits for CVE-2023-38035 may have been conducting such activities in preparation for their own subsequent malicious activities. However, given the variety of attack chains which ensued from these exploit validation activities, it is also possible that they were carried out by Initial Access Brokers (IABs) The activities which ensued from exploit validation activities identified by Darktrace fell into two categories: internal network reconnaissance and cryptocurrency mining.

Reconnaissance Activities

In one of the reconnaissance cases, immediately after receiving successful SSL connections over port 8443 from the external endpoints 190.2.131[.]204 and 45.159.248[.]179, an Ivanti Sentry system was seen making a long SSL connection over port 443 to 23.92.29[.]148, and making wget GET requests over port 4444 with the Target URIs '/ncat' and ‘/TxPortMap’ to the external endpoints, 45.86.162[.]147 and 195.123.240[.]183.  

Figure 6: Event Log data for an Ivanti Sentry system showing the device making connections to the external endpoints, 45.86.162[.]147, 23.92.29[.]148, and 195.123.240[.]183, immediately after receiving connections from rare external endpoints.

The Ivanti Sentry system then went on to scan for open SMB ports on systems within the internal network. This activity likely resulted from an attacker dropping a port scanning utility on the vulnerable Ivanti Sentry system.

Figure 7: Event Log data for an Ivanti Sentry server showing the device breaching several DETECT models after downloading a port scanning tool from 195.123.240[.]183.

In another reconnaissance case, Darktrace observed multiple wget HTTP requests with Target URIs such as ‘/awp.tar.gz’ and ‘/resp.tar.gz’ to a suspicious, external server (78.128.113[.]130).  Shortly after making these requests, the Ivanti Sentry system started to scan for open SMB ports and to respond to LLMNR queries from other internal devices. These behaviors indicate that the server may have installed an LLMNR poisoning tool, such as Responder. The Ivanti Sentry server also went on to conduct further information-gathering activities, such as LDAP reconnaissance, HTTP-based vulnerability scanning, HTTP-based password searching, and RDP port scanning.

Figure 8: Event Log data for an Ivanti Sentry system showing the device making connections to 78.128.113[.]130, scanning for an open SMB port on internal endpoints, and responding to LLMNR queries from internal endpoints.

In cases where Darktrace RESPOND was active, reconnaissance activities resulted in RESPOND enforcing the Ivanti Sentry server’s pattern of life.

Figure 9: Event Log data for an Ivanti Sentry system receiving a RESPOND action as a result of its SMB port scanning activity.
Figure 10: Event Log data for an Ivanti Sentry system receiving a RESPOND action as a result of its LDAP reconnaissance activity.

Crypto-Mining Activities

In one of the cryptomining cases, Darktrace detected an Ivanti Sentry server making SSL connections to aelix[.]xyz and mining pool endpoints after receiving successful SSL connections over port 8443 from the external endpoint, 140.228.24[.]160.

Figure 11: Event Log data for an Ivanti Sentry system showing the device contacting aelix[.]xyz and mining pool endpoints immediately after receiving connections from the external endpoint, 140.228.24[.]160.

In a cryptomining case on another customer’s network, an Ivanti Sentry server was seen making GET requests indicative of Kinsing malware infection. These requests included wget GET requests to 185.122.204[.]197 with the Target URIs ‘/unk.sh’ and ‘/se.sh’ and a combination of GET and POST requests to 185.221.154[.]208 with the User-Agent header ‘Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36’ and the Target URIs, ‘/mg’, ‘/ki’, ‘/get’, ‘/h2’, ‘/ms’, and ‘/mu’. These network-based artefacts have been observed in previous Kinsing infections [13].

Figure 12: Event Log data for an Ivanti Sentry system showing the device displaying likely Kinsing C2 activity.

On customer environments where RESPOND was active, Darktrace was able to take swift autonomous action by blocking cryptomining connection attempts to malicious command-and-control (C2) infrastructure, in this case Kinsing servers.

Figure 13: Event Log data for an Ivanti Sentry server showing the device receiving a RESPOND action after attempting to contact Kinsing C2 infrastructure.

Fortunately, due to Darktrace DETECT+RESPOND prompt identification and targeted actions against these emerging threats, coupled with remediating steps taken by affected customers’ security teams, neither the cryptocurrency mining activities nor the network reconnaissance activities led to significant disruption.  

Figure 14: Timeline of observed malicious activities.

Conclusion The inevitable presence of critical vulnerabilities in internet-facing systems underscores the perpetual challenge of defending against malicious intrusions. The near inexhaustible supply of entry routes into organizations’ networks available to malicious actors necessitates a more proactive and vigilant approach to network security.

While it is, of course, essential for organizations to secure their digital environments through the regular patching of software and keeping abreast of developing vulnerabilities that could impact their network, it is equally important to have a safeguard in place to mitigate against attackers who do manage to exploit newly discovered vulnerabilities.

In the case of Ivanti Sentry, Darktrace observed malicious actors validating exploits against affected servers on customer networks just a few days after the public disclosure of the critical vulnerability.  This activity was followed up by a variety of malicious and disruptive, activities including cryptocurrency mining and internal network reconnaissance.

Darktrace DETECT immediately detected post-exploitation activities on compromised Ivanti Sentry servers, enabling security teams to intervene at the earliest possible stage. Darktrace RESPOND, when active, autonomously inhibited detected post-exploitation activities. These DETECT detections, along with their accompanying RESPOND interventions, prevented malicious actors from being able to progress further towards their likely harmful objectives.

Credit to Sam Lister, Senior Cyber Analyst, and Trent Kessler, SOC Analyst  

Appendices

MITRE ATT&CK Mapping

Initial Access techniques:

  • Exploit Public-Facing Application (T1190)

Credential Access techniques:

  • Unsecured Credentials: Credentials In Files (T1552.001)
  • Adversary-in-the-Middle: LLMNR/NBT-NS Poisoning and SMB Relay (T1557.001)

Discovery

  • Network Service Discovery (T1046)
  • Remote System Discovery (T1018)
  • Account Discovery: Domain Account (T1087.002)

Command and Control techniques:

  • Application Layer Protocol: Web Protocols (T1071.001)
  • Ingress Tool Transfer (T1105)
  • Non-Standard Port (T1571)
  • Encrypted Channel: Asymmetric Cryptography (T1573.002)

Impact techniques

  • Resource Hijacking (T1496)
List of IoCs

Exploit testing IoCs:

·      34.77.65[.]112

·      Wget/1.14 (linux-gnu)

·      cjjovo7mhpt7geo8aqlgxp7ypod6dqaiz.oast[.]site • 178.128.16[.]97

·      curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.27.1 zlib/1.2.3 libidn/1.18 libssh2/1.4.2

·      cjk45q1chpqflh938kughtrfzgwiofns3.oast[.]site • 178.128.16[.]97

·      curl/7.29.0

Kinsing-related IoCs:

·      185.122.204[.]197

·      /unk.sh

·      /se.sh

·      185.221.154[.]208

·      185.221.154[.]208

·      45.15.158[.]124

·      Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36

·      /mg

·      /ki

·      /get

·      /h2

·      /ms

·      /mu

·      vocaltube[.]ru • 185.154.53[.]140

·      92.255.110[.]4

·      194.87.254[.]160

Responder-related IoCs:

·      78.128.113[.]130

·      78.128.113[.]34

·      /awp.tar.gz

·      /ivanty

·      /resp.tar.gz

Crypto-miner related IoCs:

·      140.228.24[.]160

·      aelix[.]xyz • 104.21.60[.]147 / 172.67.197[.]200

·      c8446f59cca2149cb5f56ced4b448c8d (JA3 client fingerprint)

·      b5eefe582e146aed29a21747a572e11c (JA3 client fingerprint)

·      pool.supportxmr[.]com

·      xmr.2miners[.]com

·      xmr.2miners[.]com

·      monerooceans[.]stream

·      xmr-eu2.nanopool[.]org

Port scanner-related IoCs:

·      122.161.66[.]161

·      192.241.235[.]32

·      45.86.162[.]147

·      /ncat

·      Wget/1.14 (linux-gnu)

·      45.159.248[.]179

·      142.93.115[.]146

·      23.92.29[.]148

·      /TxPortMap

·      195.123.240.183

·      6935a8d379e086ea1aed159b8abcb0bc8acf220bd1cbc0a84fd806f14014bca7 (SHA256 hash of downloaded file)

Darktrace DETECT Model Breaches

·      Anomalous Server Activity / New User Agent from Internet Facing System

·      Device / New User Agent

·      Anomalous Connection / New User Agent to IP Without Hostname

·      Device / New User Agent and New IP

·      Anomalous Connection / Application Protocol on Uncommon Port

·      Anomalous Connection / Callback on Web Facing Device

·      Compromise / High Volume of Connections with Beacon Score

·      Compromise / Large Number of Suspicious Failed Connections

·      Compromise / High Volume of Connections with Beacon Score

·      Compromise / Beacon for 4 Days

·      Compromise / Agent Beacon (Short Period)

·      Device / Large Number of Model Breaches

·      Anomalous Server Activity / Rare External from Server

·      Compromise / Large Number of Suspicious Successful Connections

·      Compromise / Monero Mining

·      Compromise / High Priority Crypto Currency Mining

·      Compromise / Sustained TCP Beaconing Activity To Rare Endpoint

·      Device / Internet Facing Device with High Priority Alert

·      Device / Suspicious SMB Scanning Activity

·      Device / Internet Facing Device with High Priority Alert

·      Device / Network Scan

·      Device / Unusual LDAP Bind and Search Activity

·      Compliance / Vulnerable Name Resolution

·      Device / Anomalous SMB Followed By Multiple Model Breaches

·      Device / New User Agent To Internal Server

·      Anomalous Connection / Suspicious HTTP Activity

·      Anomalous Connection / Unusual Internal Connections

·      Anomalous Connection / Suspicious HTTP Activity

·      Device / RDP Scan

·      Device / Large Number of Model Breaches

·      Compromise / Beaconing Activity To External Rare

·      Compromise / Beacon to Young Endpoint

·      Anomalous Connection / Suspicious HTTP Activity

·      Compromise / Suspicious Internal Use Of Web Protocol

·      Anomalous File / EXE from Rare External Location

·      Anomalous File / Internet Facing System File Download

·      Device / Suspicious SMB Scanning Activity

·      Device / Internet Facing Device with High Priority Alert

·      Device / Network Scan

·      Device / Initial Breach Chain Compromise

References

[1] https://www.mnemonic.io/resources/blog/ivanti-endpoint-manager-mobile-epmm-authentication-bypass-vulnerability/
[2] https://www.mnemonic.io/resources/blog/threat-advisory-remote-file-write-vulnerability-in-ivanti-epmm/
[3] https://www.mnemonic.io/resources/blog/threat-advisory-remote-code-execution-vulnerability-in-ivanti-sentry/
[4] https://www.ivanti.com/blog/cve-2023-35078-new-ivanti-epmm-vulnerability
[5] https://forums.ivanti.com/s/article/CVE-2023-35078-Remote-unauthenticated-API-access-vulnerability?language=en_US
[6] https://forums.ivanti.com/s/article/KB-Remote-unauthenticated-API-access-vulnerability-CVE-2023-35078?language=en_US
[7] https://www.ivanti.com/blog/cve-2023-35081-new-ivanti-epmm-vulnerability
[8] https://forums.ivanti.com/s/article/CVE-2023-35081-Arbitrary-File-Write?language=en_US
[9] https://forums.ivanti.com/s/article/KB-Arbitrary-File-Write-CVE-2023-35081?language=en_US
[10] https://www.ivanti.com/blog/cve-2023-38035-vulnerability-affecting-ivanti-sentry
[11] https://forums.ivanti.com/s/article/CVE-2023-38035-API-Authentication-Bypass-on-Sentry-Administrator-Interface?language=en_US
[12] https://forums.ivanti.com/s/article/KB-API-Authentication-Bypass-on-Sentry-Administrator-Interface-CVE-2023-38035?language=en_US
[13] https://isc.sans.edu/diary/Your+Business+Data+and+Machine+Learning+at+Risk+Attacks+Against+Apache+NiFi/29900

Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Sam Lister
Specialist Security Researcher

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April 17, 2026

Why Behavioral AI Is the Answer to Mythos

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How AI is breaking the patch-and-prevent security model

The business world was upended last week by the news that Anthropic has developed a powerful new AI model, Claude Mythos, which poses unprecedented risk because of its ability to expose flaws in IT systems.  

Whether it’s Mythos or OpenAI’s GPT-5.4-Cyber, which was just announced on Tuesday, supercharged AI models in the hands of hackers will allow them to carry out attacks at machine speed, much faster than most businesses can stop them.  

This news underscores a stark reality for all leaders: Patching holes alone is not a sufficient control against modern cyberattacks. You must assume that your software is already vulnerable right now. And while LLMs are very good at spotting vulnerabilities, they’re pretty bad at reliably patching them.

Project Glasswing members say it could take months or years for patches to be applied. While that work is done, enterprises must be protected against Zero-Day attacks, or security holes that are still undiscovered.  

Most cybersecurity strategies today are built like a daily multivitamin: broad, preventative, and designed to keep the system generally healthy over time. Patch regularly. Update software. Reduce known vulnerabilities. It’s necessary, disciplined, and foundational. But it’s also built for a world where the risks are well known and defined, cycles are predictable, and exposure unfolds at a manageable pace.

What happens when that model no longer holds?

The AI cyber advantage: Behavioral AI

The vulnerabilities exposed by AI systems like Mythos aren’t the well-understood risks your “multivitamin” was designed to address. They are transient, fast-emerging entry points that exist just long enough to be exploited.

In that environment, prevention alone isn’t enough. You don’t need more vitamins—you need a painkiller. The future of cybersecurity won’t be defined by how well you maintain baseline health. It will be defined by how quickly you respond when something breaks and every second counts.

That’s why behavioral AI gives businesses a durable cyber advantage. Rather than trying to figure out what the attacker looks like, it learns what “normal” looks like across the digital ecosystem of each individual business.  

That’s exactly how behavioral AI works. It understands the self, or what's normal for the organization, and then it can spot deviations in from normal that are actually early-stage attacks.

The Darktrace approach to cybersecurity

At Darktrace, we’ve been defending our 10,000 customers using behavioral AI cybersecurity developed in our AI Research Centre in Cambridge, U.K.

Darktrace was built on the understanding that attacks do not arrive neatly labeled, and that the most damaging threats often emerge before signatures, indicators, or public disclosures can catch up.  

Our AI algorithms learn in real time from your personalized business data to learn what’s normal for every person and every asset, and the flows of data within your organization. By continuously understanding “normal” across your entire digital ecosystem, Darktrace identifies and contains threats emerging from unknown vulnerabilities and compromised supply chain dependencies, autonomously curtailing attacks at machine speed.  

Security for novel threats

Darktrace is built for a world where AI is not just accelerating attacks, but fundamentally reshaping how they originate. What makes our AI so unique is that it's proven time and again to identify cyber threats before public vulnerability disclosures, such as critical Ivanti vulnerabilities in 2025 and SAP NetWeaver exploitations tied to nation-state threat actors.  

As AI reshapes how vulnerabilities are found and exploited, cybersecurity must be anchored in something more durable than a list of known flaws. It requires a real-time understanding of the business itself: what belongs, what does not, and what must be stopped immediately.

What leaders should do right now

The leadership priority must shift accordingly.

First, stop treating unknown vulnerabilities as an edge case. AI‑driven discovery makes them the norm. Security programs built primarily around known flaws, signatures, and threat intelligence will always lag behind an attacker that is operating in real time.

Second, insist on an understanding of what is actually normal across the business. When threats are novel, labels are useless. The earliest and most reliable signal of danger is abnormal behavior—systems, users, or data flows that suddenly depart from what is expected. If you cannot see that deviation as it happens, you are effectively blind during the most critical window.

Finally, assume that the next serious incident will occur before remediation guidance is available. Ask what happens in those first minutes and hours. The organizations that maintain resilience are not the ones waiting for disclosure cycles to catch up—they are the ones that can autonomously identify and contain emerging threats as they unfold.

This is the reality of cybersecurity in an AI‑shaped world. Patching and prevention remain important foundations, but the advantage now belongs to those who can respond instantly when the unpredictable occurs.

Behavioral AI is security designed not just for known threats, but for the ones that AI will discover next.

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Ed Jennings
President and CEO

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April 17, 2026

Inside ZionSiphon: Darktrace’s Analysis of OT Malware Targeting Israeli Water Systems

zionsiphonDefault blog imageDefault blog image

What is ZionSiphon?

Darktrace recently analyzed a malware sample, which identifies itself as ZionSiphon. This sample combines several familiar host-based capabilities, including privilege escalation, persistence, and removable-media propagation, with targeting logic themed around water treatment and desalination environments.

This blog details Darktrace’s investigation of ZionSiphon, focusing on how the malware identifies targets, establishes persistence, attempts to tamper with local configuration files, and scans for Operational Technology (OT)-relevant services on the local subnet. The analysis also assesses what the code suggests about the threat actor’s intended objectives and highlights where the implementation appears incomplete.

Function “ZionSiphon()” used by the malware author.
Figure 1: Function “ZionSiphon()” used by the malware author.

Targets and motivations

Israel-Focused Targeting and Messaging

The clearest indicators of intent in this sample are its hardcoded Israel-focused targeting checks and the strong political messaging found in some strings in the malware’s binary.

In the class initializer, the malware defines a set of IPv4 ranges, including “2.52.0.0-2.55.255.255”, “79.176.0.0-79.191.255.255”, and “212.150.0.0-212.150.255.255”, indicating that the author intended to restrict execution to a narrow range of addresses. All of the specified IP blocks are geographically located within Israel.

The malware obfuscates the IP ranges by encoding them in Base64.
Figure 2: The malware obfuscates the IP ranges by encoding them in Base64.

The ideological motivations behind this malware are also seemingly evident in two Base64-encoded strings embedded in the binary. The first (shown in Figure 1) is:

Netanyahu = SW4gc3VwcG9ydCBvZiBvdXIgYnJvdGhlcnMgaW4gSXJhbiwgUGFsZXN0aW5lLCBhbmQgWWVtZW4gYWdhaW5zdCBaaW9uaXN0IGFnZ3Jlc3Npb24uIEkgYW0gIjB4SUNTIi4=“, which decodes to “In support of our brothers in Iran, Palestine, and Yemen against Zionist aggression. I am "0xICS".

The second string, “Dimona = UG9pc29uaW5nIHRoZSBwb3B1bGF0aW9uIG9mIFRlbCBBdml2IGFuZCBIYWlmYQo=“, decodes to “Poisoning the population of Tel Aviv and Haifa”.  These strings do not appear to be used by the malware for any operational purpose, but they do offer an indication of the attacker’s motivations. Dimona, referenced in the second string, is an Israeli city in the Negev desert, primarily known as the site of the Shimon Peres Negev Nuclear Research Center.

The Dimona string as it appears in the decompiled malware, with the Base64-decoded text.
Figure 3: The Dimona string as it appears in the decompiled malware, with the Base64-decoded text.

The hardcoded IP ranges and propaganda‑style text suggest politically motivated intent, with Israel appearing to be a likely target.

Water and desalination-themed targeting?

The malware also includes Israel-linked strings in its target list, including “Mekorot, “Sorek”, “Hadera”, “Ashdod”, “Palmachim”, and “Shafdan”. All of the strings correspond to components of Israel’s national water infrastructure: Mekorot is Israel’s national water company responsible for managing the country’s water system, including major desalination and wastewater projects. Sorek, Hadera, Ashdod, and Palmachim are four of Israel’s five major seawater desalination plants, each producing tens of millions of cubic meters of drinking water annually. Shafdan is the country’s central wastewater treatment and reclamation facility. Their inclusion in ZionSiphon’s targeting list suggests an interest in infrastructure linked to Israel’s water sector.

Strings in the target list, all related to Israel and water treatment.
Figure 4: Strings in the target list, all related to Israel and water treatment.

Beyond geographic targeting, the sample contains a second layer of environment-specific checks aimed at water treatment and desalination systems. In the function ”IsDamDesalinationPlant()”, the malware first inspects running process names for strings such as “DesalPLC”, “ROController”, “SchneiderRO”, “DamRO”, “ReverseOsmosis”, “WaterGenix”, “RO_Pump”, “ChlorineCtrl”, “WaterPLC”, “SeaWaterRO”, “BrineControl”, “OsmosisPLC”, “DesalMonitor”, “RO_Filter”, “ChlorineDose”, “RO_Membrane”, “DesalFlow”, “WaterTreat”, and “SalinityCtrl”. These strings are directly related to desalination, reverse osmosis, chlorine handling, and plant control components typically seen in the water treatment industry.

The filesystem checks reinforce this focus. The code looks for directories such as “C:\Program Files\Desalination”, “C:\Program Files\Schneider Electric\Desal”, “C:\Program Files\IDE Technologies”, “C:\Program Files\Water Treatment”, “C:\Program Files\RO Systems”, “C:\Program Files\DesalTech”, “C:\Program Files\Aqua Solutions”, and “C:\Program Files\Hydro Systems”, as well as files including “C:\DesalConfig.ini”, “C:\ROConfig.ini”, “C:\DesalSettings.conf”, “C:\Program Files\Desalination\system.cfg”, “C:\WaterTreatment.ini”, “C:\ChlorineControl.dat”, “C:\RO_PumpSettings.ini”, and “C:\SalinityControl.ini.”

Malware Analysis

Privilege Escalation

The “RunAsAdmin” function from the malware sample.
Figure 5: The “RunAsAdmin” function from the malware sample.


The malware’s first major action is to check whether it is running with administrative rights. The “RunAsAdmin()” function calls “IsElevated()”, which retrieves the current Windows identity and checks whether it belongs to the local Administrators group. If the process is already elevated, execution proceeds normally.

The “IsElevated” function as seen in the sample.
Figure 6: The “IsElevated” function as seen in the sample.


If not, the code waits on the named mutex and launches “powershell.exe” with the argument “Start-Process -FilePath <current executable> -Verb RunAs”, after which it waits for that process to finish and then exits.

Persistence and stealth installation

Registry key creation.
Figure 7: Registry key creation.

Persistence is handled by “s1()”. This routine opens “HKCU\Software\Microsoft\Windows\CurrentVersion\Run”, retrieves the current process path, and compares it to “stealthPath”. If the current file is not already running from that location, it copies itself to the stealth path and sets the copied file’s attributes to “hidden”.

The code then creates a “Run” value named “SystemHealthCheck” pointing to the stealth path. Because “stealthPath” is built from “LocalApplicationData” and the hardcoded filename “svchost.exe”, the result is a user-level persistence mechanism that disguises the payload under a familiar Windows process name. The combination of a hidden file and a plausible-sounding autorun value suggests an intent to blend into ordinary Windows artifacts rather than relying on more complex persistence methods.

Target determination

The malware’s targeting determination is divided between “IsTargetCountry()” and “IsDamDesalinationPlant()”. The “IsTargetCountry()” function retrieves the local IPv4 address, converts it to a numeric value, and compares it against each of the hardcoded ranges stored in “ipRanges”. Only if the address falls within one of these ranges does the code move on to next string-comparison step, which ultimately determines whether the country check succeeded.

The main target validation function.
Figure 8: The main target validation function.
 The “IsTargetCountry” function.
Figure 9 : The “IsTargetCountry” function.


IsDamDesalinationPlant()” then assesses whether the host resembles a relevant OT environment. It first scans running process names for the hardcoded strings previously mentioned, followed by checks for the presence of any of the hardcoded directories or files. The intended logic is clear: the payload activates only when both a geographic condition and an environment specific condition related to desalination or water treatment are met.

Figure. 10: An excerpt of the list of strings used in the “IsDamDesalinationPlant” function

Why this version appears dysfunctional

Although the file contains sabotage, scanning, and propagation functions, the current sample appears unable to satisfy its own target-country checking function even when the reported IP falls within the specified ranges. In the static constructor, every “ipRanges” entry is associated with the same decoded string, “Nqvbdk”, derived from “TnF2YmRr”. Later, “IsTargetCountry()” (shown in Figure 8) compares that stored value against “EncryptDecrypt("Israel", 5)”.

The “EncryptDecrypt” function
Figure 11: The “EncryptDecrypt” function

As implemented, “EncryptDecrypt("Israel", 5)” does not produce “Nqvbdk”, it produces a different string. This function seems to be a basic XOR encode/decode routine, XORing the string “Israel” with value of 5. Because the resulting output does not match “Nqvbdk” the comparison always fails, even when the host IP falls within one of the specified ranges. As a result, this build appears to consistently determine that the device is not a valid target. This behavior suggests that the version is either intentionally disabled, incorrectly configured, or left in an unfinished state. In fact, there is no XOR key that would transform “Israel” into “Nqvbdk” using this function.

Self-destruct function

The “SelfDestruct” function
Figure 12: The “SelfDestruct” function

If IsTargetCountry() returns false, the malware invokes “SelfDestruct()”. This routine removes the SystemHealthCheck value from “HKCU\Software\Microsoft\Windows\CurrentVersion\Run”, writes a log file to “%TEMP%\target_verify.log” containing the message “Target not matched. Operation restricted to IL ranges. Self-destruct initiated.” and creates the batch file “%TEMP%\delete.bat”. This file repeatedly attempts to delete the malware’s executable, before deleting itself.

Local configuration file tampering

If the malware determines that the system it is on is a valid target, its first action is local file tampering. “IncreaseChlorineLevel()” checks a hardcoded list of configuration files associated with desalination, reverse osmosis, chlorine control, and water treatment OT/Industrial Control Systems (ICS).  As soon as it finds any one of these file present, it appends a fixed block of text to it and returns immediately.

The block of text appended to relevant configuration files.
Figure 13: The block of text appended to relevant configuration files.

The appended block of text contains the following entries: “Chlorine_Dose=10”, “Chlorine_Pump=ON”, “Chlorine_Flow=MAX”, “Chlorine_Valve=OPEN”, and “RO_Pressure=80”. Only if none of the hardcoded files are found does the malware proceed to its network-based OT discovery logic.

OT discovery and protocol logic

This section of the code attempts to identify devices on the local subnet, assign each one a protocol label, and then attempt protocol-specific communication. While the overall structure is consistent across protocols, the implementation quality varies significantly.

Figure 14: The ICS scanning function.

The discovery routine, “UZJctUZJctUZJct()”, obtains the local IPv4 address, reduces it to a /24 prefix, and iterates across hosts 1 through 255. For each host, it probes ports 502 (Modbus), 20000 (DNP3), and 102 (S7comm), which the code labels as “Modbus”, “DNP3”, and “S7” respectively if a valid response is received on the relevant port.

The probing is performed in parallel. For every “ip:port” combination, the code creates a task and attempts a TCP connection. The “100 ms” value in the probe routine is a per-connection timeout on “WaitOne(100, ...)”, rather than a delay between hosts or protocols. In practice, this results in a burst of short-lived OT-focused connection attempts across the local subnet.

Protocol validation and device classification

When a connection succeeds, the malware does not stop at the open port. It records the endpoint as an “ICSDevice” with an IP address, port, and protocol label. It then performs a second-stage validation by writing a NULL byte to the remote stream and reading the response that comes back.

For Modbus, the malware checks whether the first byte of the reply is between 1 and 255, for DNP3, it checks whether the first two bytes are “05 64”, and for S7comm, it checks whether the first byte is “03”. These checks are not advanced parsers, but they do show that the author understood the protocols well enough to add lightweight confirmation before sending follow-on data.

 The Modbus read request along with unfinished code for additional protocols.
Figure 15: The Modbus read request along with unfinished code for additional protocols.  

The most developed OT-specific logic is the Modbus-oriented path. In the function “IncreaseChlorineLevel(string targetIP, int targetPort, string parameter)”, the malware connects to the target and sends “01 03 00 00 00 0A”. It then reads the response and parses register values in pairs. The code then uses some basic logic to select a register index: for “Chlorine_Dose”, it looks for values greater than 0 and less than 1000; for “Turbine_Speed”, it looks for values greater than 100.

The Modbus command observed in the sample (01 03 00 00 00 0A) is a Read Holding Registers request. The first byte (0x01) represents the unit identifier, which in traditional Modbus RTU specifies the addressed slave device; in Modbus TCP, however, this value is often ignored or used only for gateway routing because device addressing is handled at the IP/TCP layer.

The second byte (0x03) is the Modbus function code indicating a Read Holding Registers request. The following two bytes (0x00 0x00) specify the starting register address, indicating that the read begins at address zero. The final two bytes (0x00 0A) define the number of registers to read, in this case ten consecutive registers. Taken together, the command requests the contents of the first ten holding registers from the target device and represents a valid, commonly used Modbus operation.

If a plausible register is found, the malware builds a six-byte Modbus write using function code “6” (Write)” and sets the value to 100 for “Chlorine_Dose”, or 0 for any other parameter. If no plausible register is found, it falls back to using hardcoded write frames. In the main malware path, however, the code only calls this function with “Chlorine_Dose".

If none of the ten registers meets the expected criteria, the malware does not abandon the operation. Instead, it defaults to a set of hardcoded Modbus write frames that specify predetermined register addresses and values. This behavior suggests that the attacker had only partial knowledge of the target environment. The initial register-scanning logic appears to be an attempt at dynamic discovery, while the fallback logic ensures that a write operation is still attempted even if that discovery fails.

Incomplete DNP3 and S7comm Logic

The DNP3 and S7comm branches appear much less complete. In “GetCommand()”, the DNP3 path returns the fixed byte sequence “05 64 0A 0C 01 02”, while the S7comm path returns “03 00 00 13 0E 00”. Neither sequence resembles a fully formed command for the respective protocol.

In the case of the S7comm section, the five byte‑ sequence found in the malware sample (05 00 1C 22 1E) most closely matches the beginning of an S7comm parameter block, specifically the header of a “WriteVar (0x05)” request, which is the S7comm equivalent of a Modbus register write operation. In the S7comm protocol, the first byte of a parameter block identifies the function code,  but the remaining bytes in this case do not form a valid item definition. A vaild S7 WriteVar parameter requires at least one item and a full 11-byte variable-specification structure. By comparison this 5‑ byte array is far too short to be a complete or usable command.

The zero item count (0x00) and the trailing three bytes appear to be either uninitialized data or the beginning of an incomplete address field. Together, these details suggest that the attacker likely intended to implement S7 WriteVar functionality, like the Modbus function, but left this portion of the code unfinished.

The DNP3 branch of the malware also appears to be only partially implemented. The byte sequence returned by the DNP3 path (05 64 0A 0C 01 02) begins with the correct two‑byte DNP3 link‑layer sync header (0x05 0x64) and includes additional bytes that resemble the early portion of a link‑layer header. However, the sequence is far too short to constitute a valid DNP3 frame. It lacks the required destination and source address fields, the 16‑bit CRC blocks, and any application‑layer payload in which DNP3 function code would reside. As a result, this fragment does not represent a meaningful DNP3 command.

The incomplete S7 and DNP3 fragments suggest that these protocol branches were still in a developmental or experimental state when the malware was compiled. Both contain protocol‑accurate prefixes, indicating an intent to implement multi‑protocol OT capabilities, however for reasons unknow, these sections were not fully implemented or could not be completed prior to deployment.

USB Propagation

The malware also includes a removable-media propagation mechanism. The “sdfsdfsfsdfsdfqw()” function scans for drives, selects those identified as removable, and copies the hidden payload to each one as “svchost.exe” if it is not already present. The copied executable is marked with the “Hidden” and “System” attributes to reduce visibility.

The malware then calls “CreateUSBShortcut()”, which uses “WScript.Shell” to create .lnk files for each file in the removable drive root. Each shortcut’s TargetPath is set to the hidden malware copy, the icon is set to “shell32.dll, 4” (this is the windows genericfile icon), and the original file is hidden. Were a victim to click this “file,” they would unknowingly run the malware.

Figure 14:The creation of the shortcut on the USB device.

Key Insights

ZionSiphon represents a notable, though incomplete, attempt to build malware capable of malicious interaction with OT systems targeting water treatment and desalination environments.

While many of ZionSiphon’s individual capabilities align with patterns commonly found in commodity malware, the combination of politically motivated messaging, Israel‑specific IP targeting, and an explicit focus on desalination‑related processes distinguishes it from purely opportunistic threats. The inclusion of Modbus sabotage logic, filesystem tampering targeting chlorine and pressure control, and subnet‑wide ICS scanning demonstrates a clear intent to interact directly with industrial processes controllers and to cause significant damage and potential harm, rather than merely disrupt IT endpoints.

At the same time, numerous implementation flaws, most notably the dysfunctional country‑validation logic and the placeholder DNP3 and S7comm components, suggest that analyzed version is either a development build, a prematurely deployed sample, or intentionally defanged for testing purposes. Despite these limitations, the overall structure of the code likely indicates a threat actor experimenting with multi‑protocol OT manipulation, persistence within operational networks, and removable‑media propagation techniques reminiscent of earlier ICS‑targeting campaigns.

Even in its unfinished state, ZionSiphon underscores a growing trend in which threat actors are increasingly experimenting with OT‑oriented malware and applying it to the targeting of critical infrastructure. Continued monitoring, rapid anomaly detection, and cross‑visibility between IT and OT environments remain essential for identifying early‑stage threats like this before they evolve into operationally viable attacks.

Credit to Calum Hall (Cyber Analyst)
Edited by Ryan Traill (Content Manager)

References

1.        https://www.virustotal.com/gui/file/07c3bbe60d47240df7152f72beb98ea373d9600946860bad12f7bc617a5d6f5f/details

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About the author
Calum Hall
Technical Content Researcher
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