October 14, 2024

How Triada Affects Banking and Communication Apps

Explore the intricacies of the Triada Trojan and its targeting of communication and banking apps. Learn how to safeguard against this threat.

Written by

Justin Torres

Cyber Analyst

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

Justin Torres

Cyber Analyst

Oct 2024

The rise of android malware

Recently, there has been a significant increase in malware strains targeting mobile devices, with a growing number of Android-based malware families, such as banking trojans, which aim to steal sensitive banking information from organizations and individuals worldwide.

These malware families attempt to access users’ accounts to steal online banking credentials and cookies, bypass multi-factor authentication (MFA), and conduct automatic transactions to steal funds [1]. They often masquerade as legitimate software or communications from social media platforms to compromise devices. Once installed, they use tactics such as keylogging, dumping cached credentials, and searching the file system for stored passwords to steal credentials, take over accounts, and potentially perform identity theft [1].

One recent example is the Antidot Trojan, which infects devices by disguising itself as an update page for Google Play. It establishes a command-and-control (C2) channel with a server, allowing malicious actors to execute commands and collect sensitive data [2].

Despite these malware’s ability to evade detection by standard security software, for example, by changing their code [3], Darktrace recently detected another Android malware family, Triada, communicating with a C2 server and exfiltrating data.

Triada: Background and tactics

First surfacing in 2016, Triada is a modular mobile trojan known to target banking and financial applications, as well as popular communication applications like WhatsApp, Facebook, and Google Mail [4]. It has been deployed as a backdoor on devices such as CTV boxes, smartphones, and tablets during the supply chain process [5]. Triada can also be delivered via drive-by downloads, phishing campaigns, smaller trojans like Leech, Ztorg, and Gopro, or more recently, as a malicious module in applications such as unofficial versions of WhatsApp, YoWhatsApp, and FM WhatsApp [6] [7].

How does Triada work?

Once downloaded onto a user’s device, Triada collects information about the system, such as the device’s model, OS version, SD card space, and list of installed applications, and sends this information to a C2 server. The server then responds with a configuration file containing the device’s personal identification number and settings, including the list of modules to be installed.

After a device has been successfully infected by Triada, malicious actors can monitor and intercept incoming and outgoing texts (including two-factor authentication messages), steal login credentials and credit card information from financial applications, divert in-application purchases to themselves, create fake messaging and email accounts, install additional malicious applications, infect devices with ransomware, and take control of the camera and microphone [4] [7].

For devices infected by unofficial versions of WhatsApp, which are downloaded from third-party app stores [9] and from mobile applications such as Snaptube and Vidmate , Triada collects unique device identifiers, information, and keys required for legitimate WhatsApp to work and sends them to a remote server to register the device [7] [12]. The server then responds by sending a link to the Triada payload, which is downloaded and launched. This payload will also download additional malicious modules, sign into WhatsApp accounts on the target’s phone, and request the same permissions as the legitimate WhatsApp application, such as access to SMS messages. If granted, a malicious actor can sign the user up for paid subscriptions without their knowledge. Triada then collects information about the user’s device and mobile operator and sends it to the C2 server [9] [12].

How does Triada avoid detection?

Triada evades detection by modifying the Zygote process, which serves as a template for every application in the Android OS. This enables the malware to become part of every application launched on a device [3]. It also substitutes system functions and conceals modules from the list of running processes and installed apps, ensuring that the system does not raise the alarm [3]. Additionally, as Triada connects to a C2 server on the first boot, infected devices remain compromised even after a factory reset [4].

Triada attack overview

Across multiple customer deployments, devices were observed making a large number of connections to a range of hostnames, primarily over encrypted SSL and HTTPS protocols. These hostnames had never previously been observed on the customers’ networks and appear to be algorithmically generated. Examples include “68u91.66foh90o[.]com”, “92n7au[.]uhabq9[.]com”, “9yrh7.mea5ms[.]com”, and “is5jg.3zweuj[.]com”.

Figure 1: External Sites Summary Graph showing the rarity of the hostname “92n7au[.]uhabq9[.]com” on a customer network.

Most of the IP addresses associated with these hostnames belong to an ASN associated with the cloud provider Alibaba (i.e., AS45102 Alibaba US Technology Co., Ltd). These connections were made over a range of high number ports over 1000, most commonly over 30000 such as 32091, which Darktrace recognized as extremely unusual for the SSL and HTTPS protocols.

Figure 2: Screenshot of a Model Alert Event log showing a device connecting to the endpoint “is5jg[.]3zweuj[.]com” over port 32091.

On several customer deployments, devices were seen exfiltrating data to hostnames which also appeared to be algorithmically generated. This occurred via HTTP POST requests containing unusual URI strings that were made without a prior GET request, indicating that the infected device was using a hardcoded list of C2 servers.

Figure 3: Screenshot of a Model Alert Event Log showing the device posting the string “i8xps1” to the hostname “72zf6.rxqfd[.]com.

Figure 4: Screenshot of a Model Alert Event Log showing the device posting the string “sqyjyadwwq” to the hostname “9yrh7.mea5ms[.]com”.

These connections correspond with reports that devices affected by Triada communicate with the C2 server to transmit their information and receive instructions for installing the payload.

A number of these endpoints have communicating files associated with the unofficial WhatsApp versions YoWhatsApp and FM WhatsApp [11] [12] [13] . This could indicate that the devices connecting to these endpoints were infected via malicious modules in the unofficial versions of WhatsApp, as reported by open-source intelligence (OSINT) [10] [12]. It could also mean that the infected devices are using these connections to download additional files from the C2 server, which could infect systems with additional malicious modules related to Triada.

Moreover, on certain customer deployments, shortly before or after connecting to algorithmically generated hostnames with communicating files linked to YoWhatsApp and FM WhatsApp, devices were also seen connecting to multiple endpoints associated with WhatsApp and Facebook.

Figure 5: Screenshot from a device’s event log showing connections to endpoints associated with WhatsApp shortly after it connected to “9yrh7.mea5ms[.]com”.

These surrounding connections indicate that Triada is attempting to sign in to the users’ WhatsApp accounts on their mobile devices to request permissions such as access to text messages. Additionally, Triada sends information about users’ devices and mobile operators to the C2 server.

The connections made to the algorithmically generated hostnames over SSL and HTTPS protocols, along with the HTTP POST requests, triggered multiple Darktrace models to alert. These models include those that detect connections to potentially algorithmically generated hostnames, connections over ports that are highly unusual for the protocol used, unusual connectivity over the SSL protocol, and HTTP POSTs to endpoints that Darktrace has determined to be rare for the network.

Conclusion

Recently, the use of Android-based malware families, aimed at stealing banking and login credentials, has become a popular trend among threat actors. They use this information to perform identity theft and steal funds from victims worldwide.

Across affected customers, multiple devices were observed connecting to a range of likely algorithmically generated hostnames over SSL and HTTPS protocols. These devices were also seen sending data out of the network to various hostnames via HTTP POST requests without first making a GET request. The URIs in these requests appeared to be algorithmically generated, suggesting the exfiltration of sensitive network data to multiple Triada C2 servers.

This activity highlights the sophisticated methods used by malware like Triada to evade detection and exfiltrate data. It underscores the importance of advanced security measures and anomaly-based detection systems to identify and mitigate such mobile threats, protecting sensitive information and maintaining network integrity.

Credit to: Justin Torres (Senior Cyber Security Analyst) and Anna Gilbertson (Cyber Security Analyst).

Appendices

Darktrace Model Detections

Model Alert Coverage

Anomalous Connection / Application Protocol on Uncommon Port

Anomalous Connection / Multiple Connections to New External TCP Port

Anomalous Connection / Multiple HTTP POSTS to Rare Hostname

Anomalous Connections / Multiple Failed Connections to Rare Endpoint

Anomalous Connection / Suspicious Expired SSL

Compromise / DGA Beacon

Compromise / Domain Fluxing

Compromise / Fast Beaconing to DGA

Compromise / Sustained SSL or HTTP Increase

Compromise / Unusual Connections to Rare Lets Encrypt

Unusual Activity / Unusual External Activity

‍

AI Analyst Incident Coverage

Unusual Repeated Connections to Multiple Endpoints

Possible SSL Command and Control

Unusual Repeated Connections

List of Indicators of Compromise (IoCs)

Ioc – Type - Description

is5jg[.]3zweuj[.]com - Hostname - Triada C2 Endpoint
68u91[.]66foh90o[.]com - Hostname - Triada C2 Endpoint
9yrh7[.]mea5ms[.]com - Hostname - Triada C2 Endpoint
92n7au[.]uhabq9[.]com - Hostname - Triada C2 Endpoint
4a5x2[.]fs4ah[.]com - Hostname - Triada C2 Endpoint
jmll4[.]66foh90o[.]com - Hostname - Triada C2 Endpoint
mrswd[.]wo87sf[.]com - Hostname - Triada C2 Endpoint
lptkw[.]s4xx6[.]com - Hostname - Triada C2 Endpoint
ya27fw[.]k6zix6[.]com - Hostname - Triada C2 Endpoint
w0g25[.]66foh90o[.]com - Hostname - Triada C2 Endpoint
kivr8[.]wd6vy[.]com - Hostname - Triada C2 Endpoint
iuwe64[.]ct8pc6[.]com - Hostname - Triada C2 Endpoint
qefgn[.]8z0le[.]com - Hostname - Triada C2 Endpoint
a6y0x[.]xu0h7[.]com - Hostname - Triada C2 Endpoint
wewjyw[.]qb6ges[.]com - Hostname - Triada C2 Endpoint
vx9dle[.]n0qq3z[.]com - Hostname - Triada C2 Endpoint
72zf6[.]rxqfd[.]com - Hostname - Triada C2 Endpoint
dwq[.]fsdw4f[.]com - Hostname - Triada C2 Endpoint
tqq6g[.]66foh90o[.]com - Hostname - Triada C2 Endpoint
1rma1[.]4f8uq[.]com - Hostname - Triada C2 Endpoint
0fdwa[.]7j3gj[.]com - Hostname - Triada C2 Endpoint
5a7en[.]1e42t[.]com - Hostname - Triada C2 Endpoint
gmcp4[.]1e42t[.]com - Hostname - Triada C2 Endpoint
g7190[.]rt14v[.]com - Hostname - Triada C2 Endpoint
goyvi[.]2l2wa[.]com - Hostname - Triada C2 Endpoint
zq6kk[.]ca0qf[.]com - Hostname - Triada C2 Endpoint
sv83k[.]bn3avv[.]com - Hostname - Triada C2 Endpoint
9sae7h[.]ct8pc6[.]com - Hostname - Triada C2 Endpoint
jpygmk[.]qt7tqr[.]com - Hostname - Triada C2 Endpoint
av2wg[.]rt14v[.]com - Hostname - Triada C2 Endpoint
ugbrg[.]osz1p[.]com - Hostname - Triada C2 Endpoint
hw2dm[.]wtws9k[.]com - Hostname - Triada C2 Endpoint
kj9atb[.]hai8j1[.]com - Hostname - Triada C2 Endpoint
pls9b[.]b0vb3[.]com - Hostname - Triada C2 Endpoint
8rweau[.]j7e7r[.]com - Hostname - Triada C2 Endpoint
wkc5kn[.]j7e7r[.]com - Hostname - Triada C2 Endpoint
v58pq[.]mpvflv[.]com - Hostname - Triada C2 Endpoint
zmai4k[.]huqp3e[.]com - Hostname - Triada C2 Endpoint
eajgum[.]huqp3e[.]com - Hostname - Triada C2 Endpoint
mxl9zg[.]kv0pzv[.]com - Hostname - Triada C2 Endpoint
ad1x7[.]mea5ms[.]com - Hostname - Triada C2 Endpoint
ixhtb[.]s9gxw8[.]com - Hostname - Triada C2 Endpoint
vg1ne[.]uhabq9[.]com - Hostname - Triada C2 Endpoint
q5gd0[.]birxpk[.]com - Hostname - Triada C2 Endpoint
dycsw[.]h99n6[.]com - Hostname - Triada C2 Endpoint
a3miu[.]h99n6[.]com - Hostname - Triada C2 Endpoint
qru62[.]5qwu8b5[.]com - Hostname - Triada C2 Endpoint
3eox8[.]abxkoop[.]com - Hostname - Triada C2 Endpoint
0kttj[.]bddld[.]com - Hostname - Triada C2 Endpoint
gjhdr[.]xikuj[.]com - Hostname - Triada C2 Endpoint
zq6kk[.]wm0hd[.]com - Hostname - Triada C2 Endpoint
8.222.219[.]234 - IP Address - Triada C2 Endpoint
8.222.244[.]205 - IP Address - Triada C2 Endpoint
8.222.243[.]182 - IP Address - Triada C2 Endpoint
8.222.240[.]127 - IP Address - Triada C2 Endpoint
8.219.123[.]139 - IP Address - Triada C2 Endpoint
8.219.196[.]124 - IP Address - Triada C2 Endpoint
8.222.217[.]73 - IP Address - Triada C2 Endpoint
8.222.251[.]253 - IP Address - Triada C2 Endpoint
8.222.194[.]254 - IP Address - Triada C2 Endpoint
8.222.251[.]34 - IP Address - Triada C2 Endpoint
8.222.216[.]105 - IP Address - Triada C2 Endpoint
47.245.83[.]167 - IP Address - Triada C2 Endpoint
198.200.54[.]56 - IP Address - Triada C2 Endpoint
47.236.113[.]126 - IP Address - Triada C2 Endpoint
47.241.47[.]128 - IP Address - Triada C2 Endpoint
/iyuljwdhxk - URI - Triada C2 URI
/gvuhlbzknh - URI - Triada C2 URI
/sqyjyadwwq - URI - Triada C2 URI
/cncyz3 - URI - Triada C2 URI
/42k0zk - URI - Triada C2 URI
/75kdl5 - URI - Triada C2 URI
/i8xps1 - URI - Triada C2 URI
/84gcjmo - URI - Triada C2 URI
/fkhiwf - URI - Triada C2 URI

MITRE ATT&CK Mapping

Technique Name - Tactic - ID - Sub-Technique of

Data Obfuscation - COMMAND AND CONTROL - T1001

Non-Standard Port - COMMAND AND CONTROL - T1571

Standard Application Layer Protocol - COMMAND AND CONTROL ICS - T0869

Non-Application Layer Protocol - COMMAND AND CONTROL - T1095

Masquerading - EVASION ICS - T0849

Man in the Browser - COLLECTION - T1185

Web Protocols - COMMAND AND CONTROL - T1071.001 -T1071

External Proxy - COMMAND AND CONTROL - T1090.002 - T1090

Domain Generation Algorithms - COMMAND AND CONTROL - T1568.002 - T1568

Web Services - RESOURCE DEVELOPMENT - T1583.006 - T1583

DNS - COMMAND AND CONTROL - T1071.004 - T1071

Fast Flux DNS - COMMAND AND CONTROL - T1568.001 - T1568

One-Way Communication - COMMAND AND CONTROL - T1102.003 - T1102

Digital Certificates - RESOURCE DEVELOPMENT - T1587.003 - T1587

References

[1] https://www.checkpoint.com/cyber-hub/cyber-security/what-is-trojan/what-is-a-banking-trojan/

[2] https://cyberfraudcentre.com/the-rise-of-the-antidot-android-banking-trojan-a-comprehensive-guide

[3] https://www.zimperium.com/glossary/banking-trojans/

[4] https://www.geeksforgeeks.org/what-is-triada-malware/

[5] https://www.infosecurity-magazine.com/news/malware-infected-devices-retailers/

[6] https://www.pcrisk.com/removal-guides/24926-triada-trojan-android

[7] https://securelist.com/malicious-whatsapp-mod-distributed-through-legitimate-apps/107690/

[8] https://securityboulevard.com/2024/02/impact-of-badbox-and-peachpit-malware-on-android-devices/

[9] https://threatpost.com/custom-whatsapp-build-malware/168892/

[10] https://securelist.com/triada-trojan-in-whatsapp-mod/103679/

[11] https://www.virustotal.com/gui/domain/is5jg.3zweuj.com/relations

[12] https://www.virustotal.com/gui/domain/92n7au.uhabq9.com/relations

[13] https://www.virustotal.com/gui/domain/68u91.66foh90o.com/relations

Written by

Justin Torres

Cyber Analyst

Inside the SOC

Written by

Justin Torres

Cyber Analyst

Product Marketing Manager, Network Detection & Response

Watch the NIS2 Webinar

Blog

Network

November 13, 2025

Unmasking Vo1d: Inside Darktrace’s Botnet Detection

What is vo1d APK malware?

Vo1d malware first appeared in the wild in September 2024 and has since evolved into one of the most widespread Android botnets ever observed. This large-scale Android malware primarily targets smart TVs and low-cost Android TV boxes. Initially, Vo1d was identified as a malicious backdoor capable of installing additional third-party software [1]. Its functionality soon expanded beyond the initial infection to include deploying further malicious payloads, running proxy services, and conducting ad fraud operations. By early 2025, it was estimated that Vo1d had infected 1.3 to 1.6 million devices worldwide [2].

From a technical perspective, Vo1d embeds components into system storage to enable itself to download and execute new modules at any time. External researchers further discovered that Vo1d uses Domain Generation Algorithms (DGAs) to create new command-and-control (C2) domains, ensuring that regardless of existing servers being taken down, the malware can quickly reconnect to new ones. Previous published analysis identified dozens of C2 domains and hundreds of DGA seeds, along with new downloader families. Over time, Vo1d has grown increasingly sophisticated with clear signs of stronger obfuscation and encryption methods designed to evade detection [2].

Darktrace’s coverage

Earlier this year, Darktrace observed a surge in Vo1d-related activity across customer environments, with the majority of affected customers based in South Africa. Devices that had been quietly operating as expected began exhibiting unusual network behavior, including excessive DNS lookups. Open-source intelligence (OSINT) has long highlighted South Africa as one of the countries most impacted by Vo1d infections [2].

What makes the recent activity particularly interesting is that the surge observed by Darktrace appears to be concentrated specifically in South African environments. This localized spike suggests that a significant number of devices may have been compromised, potentially due to vulnerable software, outdated firmware, or even preloaded malware. Regions with high prevalence of low-cost, often unpatched devices are especially susceptible, as these everyday consumer electronics can be quietly recruited into the botnet’s network. This specifically appears to be the case with South Africa, where public reporting has documented widespread use of low-cost boxes, such as non-Google-certified Android TV sticks, that frequently ship with outdated firmware [3].

The initial triage highlighted the core mechanism Vo1d uses to remain resilient: its use of DGA. A DGA deterministically creates a large list of pseudo-random domain names on a predictable schedule. This enables the malware to compute hundreds of candidate domains using the same algorithm, instead of using a hard-coded single C2 hostname that defenders could easily block or take down. To ensure reproducible from the infected device’s perspective, Vo1d utilizes DGA seeds. These seeds might be a static string, a numeric value, or a combination of underlying techniques that enable infected devices to generate the same list of candidate domains for a time window, provided the same DGA code, seed, and date are used.

Interestingly, Vo1d’s DGA seeds do not appear to be entirely unpredictable, and the generated domains lack fully random-looking endings. As observed in Figure 1, there is a clear pattern in the names generated. In this case, researchers identified that while the first five characters would change to create the desired list of domain names, the trailing portion remained consistent as part of the seed: 60b33d7929a, which OSINT sources have linked to the Vo1d botnet. [2]. Darktrace’s Threat Research team also identified a potential second DGA seed, with devices in some cases also engaging in activity involving hostnames matching the regular expression /[a-z]{5}fc975904fc9\.(com|top|net). This second seed has not been reported by any OSINT vendors at the time of writing.

Another recurring characteristic observed across multiple cases was the choice of top-level domains (TLDs), which included .com, .net, and .top.

Figure 1: Advanced Search results showing DNS lookups, providing a glimpse on the DGA seed utilized.

The activity was detected by multiple models in Darktrace / NETWORK, which triggered on devices making an unusually large volume of DNS requests for domains uncommon across the network.

During the network investigation, Darktrace analysts traced Vo1d’s infrastructure and uncovered an interesting pattern related to responder ASNs. A significant number of connections pointed to AS16509 (AMAZON-02). By hosting redirectors or C2 nodes inside major cloud environments, Vo1d is able to gain access to highly available and geographically diverse infrastructure. When one node is taken down or reported, operators can quickly enable a new node under a different IP within the same ASN. Another feature of cloud infrastructure that hardens Vo1d’s resilience is the fact that many organizations allow outbound connections to cloud IP ranges by default, assuming they are legitimate. Despite this, Darktrace was able to identify the rarity of these endpoints, identifying the unusualness of the activity.

Analysts further observed that once a generated domain successfully resolved, infected devices consistently began establishing outbound connections to ephemeral port ranges like TCP ports 55520 and 55521. These destination ports are atypical for standard web or DNS traffic. Even though the choice of high-numbered ports appears random, it is likely far from not accidental. Commonly used ports such as port 80 (HTTP) or 443 (HTTPS) are often subject to more scrutiny and deeper inspection or content filtering, making them riskier for attackers. On the other hand, unregistered ports like 55520 and 55521 are less likely to be blocked, providing a more covert channel that blends with outbound TCP traffic. This tactic helps evade firewall rules that focus on common service ports. Regardless, Darktrace was able to identify external connections on uncommon ports to locations that the network does not normally visit.

The continuation of the described activity was identified by Darktrace’s Cyber AI Analyst, which correlated individual events into a broader interconnected incident. It began with the multiple DNS requests for the algorithmically generated domains, followed by repeated connections to rare endpoints later confirmed as attacker-controlled infrastructure. Cyber AI Analyst’s investigation further enabled it to categorize the events as part of the “established foothold” phase of the attack.

Figure 2: Cyber AI Analyst incident illustrating the transition from DNS requests for DGA domains to connections with resolved attacker-controlled infrastructure.

Conclusion

The observations highlighted in this blog highlight the precision and scale of Vo1d’s operations, ranging from its DGA-generated domains to its covert use of high-numbered ports. The surge in affected South African environments illustrate how regions with many low-cost, often unpatched devices can become major hubs for botnet activity. This serves as a reminder that even everyday consumer electronics can play a role in cybercrime, emphasizing the need for vigilance and proactive security measures.

Credit to Christina Kreza (Cyber Analyst & Team Lead) and Eugene Chua (Principal Cyber Analyst & Team Lead)

Edited by Ryan Traill (Analyst Content Lead)

‍