Uncover New Malicious Email Payloads in Google Translate
03
Nov 2022
Discover how threat actors are concealing malicious email payloads within Google Translate domains. Learn how Darktrace responds to these attacks effectively.
Darktrace recently detected a new technique used by threat actors to deliver malicious email payloads. The malicious link was observed hidden within a legitimate domain, namely Google Translate services. To understand its abusive capabilities, it is important to first understand a benign case of how these links are created.
Google often provides a ‘Translate this page’ option for sites written in a different language to the default browser language.
Figure 1: A google search result for an international company E.g ‘Crédit Agricole’ gives the option to translate the page from French to English.
Figure 2: When clicked, the browser displays a link with a translate[.]goog domain, and the original domain, credit-agricole[.]fr, becomes the link’s subdomain.
When this feature is exploited by threat actors it can be particularly dangerous, as legacy security products that rely on ‘known’ or ‘safe’ domain-based detection are likely to register these emails as safe and provide no protective actions. If a recipient were to click on the malicious link, they could risk losing their credentials or even compromising their machine.
In contrast, Darktrace/Email has been able to consistently identify and action emails from such campaigns. This blog will discuss one of these events.
The Campaign
The apparent motive in this attack was to harvest credentials and/or deploy malware on the recipient’s device. Credential harvesting can lead to the sale of credentials on the dark web, or the attacker may choose to leverage those credentials in subsequent attacks. Both harvesting credentials and deploying malware have severe potential ramifications, including but not limited to sensitive company data leaks and financial loss.
During this attack, the threat actor sent similar emails to a group of recipients in a short space of time. The recipients were not normally associated with each other and Darktrace swiftly identified them as unsolicited bulk mail. The new technique that was leveraged included using Google’s translate services to share malicious links using legitimate seeming domains. The malicious host was visible within the subdomain ‘636416-selcdn-ru[.]translate[.]goog’.
When clicked, the link displays a google translate page stating, “Can’t translate this page”. There is then a hyperlink, “Go to original page”, that brings the user to the malicious host- 636416[.]selcdn[.]ru. Finally, the host displays a fake webmail portal login. If a user engages, the attacker can harvest their credentials to either sell or use in subsequent attacks.
Figure 3- The Google Translate page that is displayed once clicking on the full link within the email. The hyperlink at the bottom of the image is where the user is redirected by clicking “Go to original page”. It is there that the fake webmail portal login is then displayed.
Darktrace Coverage
As the malicious emails contained links to ‘safe’ Google Translate domains, most email security products would not characterize the links as suspicious. However, Darktrace/Email levies hundreds of metrics to identify whether emails belong in a recipient’s inbox. In this case Darktrace highlighted anomalies including rare subdomains, links containing unknown redirects, emails from spoofed freemail accounts and senders that had sent a relatively large number of emails within a short time frame. Furthermore, the attacker had never sent any previous emails to the organization prior to this email campaign.
On top of providing visibility, the RESPOND function of Darktrace/Email took action autonomously and instantaneously without any human confirmation required. These actions included locking links and holding malicious emails.
Figure 4- Darktrace/Email overview tab shows the Anomaly Indicators section as well as the History, Association, and Validation information of this sender.
Figure 5 - The Darktrace RESPOND/Email model tab displays all models that triggered on the email and the associated actions. The most severe delivery action supersedes the others, so here the email was held.
Concluding Thoughts
Threat actors are continuously updating the way they deliver malicious payloads within emails. While this particular email campaign utilized Google Translate domains to hide malicious links, subsequent attacks may well be seen leveraging other legitimate domains. Companies are only as strong as their weakest link; a single compromised internal email account can be used to send phishing emails to internal recipients, collect sensitive company information, inject malware onto the device, and more. Security tools must evolve to focus on anomalies within the email, rather than relying on rules or signatures of previously seen attacks. Furthermore, email tools must be able to autonomously respond as soon as the malicious emails enter the company’s environment. Only with these precautions will the risks associated with malicious emails be mitigated.
Thanks to Steven Haworth and Steven Sosa for their contributions.
Appendices
Relevant Darktrace Model Detections
· Association / Anomalous Association
· Association / New Sender
· Association / Unknown Sender
· Association / Unlikely Recipient Association
· High Antigena Anomaly [part of the RESPOND functionality]
· Link / Low Link Association
· Link / Low Link Association and Unknown Sender
· Link / New Correspondent Classified Link
· Link / New Unknown Redirect
· Link / Open Redirect
· Link / Visually Prominent Link
· Spam / Unsolicited Bulk Mail
· Spoof / Spoofed Freemail
· Unusual / New Sender Wide Distribution
· Unusual / Sender Surge
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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.
Bytesize Security: Insider Threats in Google Workspace
What is an insider threat?
An insider threat is a cyber risk originating from within an organization. These threats can involve actions such as an employee inadvertently clicking on a malicious link (e.g., a phishing email) or an employee with malicious intent conducting data exfiltration for corporate sabotage.
Insiders often exploit their knowledge and access to legitimate corporate tools, presenting a continuous risk to organizations. Defenders must protect their digital estate against threats from both within and outside the organization.
For example, in the summer of 2024, Darktrace / IDENTITY successfully detected a user in a customer environment attempting to steal sensitive data from a trusted Google Workspace service. Despite the use of a legitimate and compliant corporate tool, Darktrace identified anomalies in the user’s behavior that indicated malicious intent.
Attack overview: Insider threat
In June 2024, Darktrace detected unusual activity involving the Software-as-a-Service (SaaS) account of a former employee from a customer organization. This individual, who had recently left the company, was observed downloading a significant amount of data in the form of a “.INDD” file (an Adobe InDesign document typically used to create page layouts [1]) from Google Drive.
While the use of Google Drive and other Google Workspace platforms was not unexpected for this employee, Darktrace identified that the user had logged in from an unfamiliar and suspicious IPv6 address before initiating the download. This anomaly triggered a model alert in Darktrace / IDENTITY, flagging the activity as potentially malicious.
Figure 1: A Model Alert in Darktrace / IDENTITY showing the unusual “.INDD” file being downloaded from Google Workspace.
Following this detection, the customer reached out to Darktrace’s Security Operations Center (SOC) team via the Security Operations Support service for assistance in triaging and investigating the incident further. Darktrace’s SOC team conducted an in-depth investigation, enabling the customer to identify the exact moment of the file download, as well as the contents of the stolen documents. The customer later confirmed that the downloaded files contained sensitive corporate data, including customer details and payment information, likely intended for reuse or sharing with a new employer.
In this particular instance, Darktrace’s Autonomous Response capability was not active, allowing the malicious insider to successfully exfiltrate the files. If Autonomous Response had been enabled, Darktrace would have immediately acted upon detecting the login from an unusual (in this case 100% rare) location by logging out and disabling the SaaS user. This would have provided the customer with the necessary time to review the activity and verify whether the user was authorized to access their SaaS environments.
Conclusion
Insider threats pose a significant challenge for traditional security tools as they involve internal users who are expected to access SaaS platforms. These insiders have preexisting knowledge of the environment, sensitive data, and how to make their activities appear normal, as seen in this case with the use of Google Workspace. This familiarity allows them to avoid having to use more easily detectable intrusion methods like phishing campaigns.
Darktrace’s anomaly detection capabilities, which focus on identifying unusual activity rather than relying on specific rules and signatures, enable it to effectively detect deviations from a user’s expected behavior. For instance, an unusual login from a new location, as in this example, can be flagged even if the subsequent malicious activity appears innocuous due to the use of a trusted application like Google Drive.
Credit to Vivek Rajan (Cyber Analyst) and Ryan Traill (Analyst Content Lead)
Appendices
Darktrace Model Detections
SaaS / Resource::Unusual Download Of Externally Shared Google Workspace File
RansomHub Ransomware: Darktrace’s Investigation of the Newest Tool in ShadowSyndicate's Arsenal
What is ShadowSyndicate?
ShadowSyndicate, also known as Infra Storm, is a threat actor reportedly active since July 2022, working with various ransomware groups and affiliates of ransomware programs, such as Quantum, Nokoyawa, and ALPHV. This threat actor employs tools like Cobalt Strike, Sliver, IcedID, and Matanbuchus malware in its attacks. ShadowSyndicate utilizes the same SSH fingerprint (1ca4cbac895fc3bd12417b77fc6ed31d) on many of their servers—85 as of September 2023. At least 52 of these servers have been linked to the Cobalt Strike command and control (C2) framework [1].
What is RansomHub?
First observed following the FBI's takedown of ALPHV/BlackCat in December 2023, RansomHub quickly gained notoriety as a Ransomware-as-a-Service (RaaS) operator. RansomHub capitalized on the law enforcement’s disruption of the LockBit group’s operations in February 2024 to market themselves to potential affiliates who had previously relied on LockBit’s encryptors. RansomHub's success can be largely attributed to their aggressive recruitment on underground forums, leading to the absorption of ex-ALPHV and ex-LockBit affiliates. They were one of the most active ransomware operators in 2024, with approximately 500 victims reported since February, according to their Dedicated Leak Site (DLS) [2].
ShadowSyndicate and RansomHub
External researchers have reported that ShadowSyndicate had as many as seven different ransomware families in their arsenal between July 2022, and September 2023. Now, ShadowSyndicate appears to have added RansomHub’s their formidable stockpile, becoming an affiliate of the RaaS provider [1].
Darktrace’s analysis of ShadowSyndicate across its customer base indicates that the group has been leveraging RansomHub ransomware in multiple attacks in September and October 2024. ShadowSyndicate likely shifted to using RansomHub due to the lucrative rates offered by this RaaS provider, with affiliates receiving up to 90% of the ransom—significantly higher than the general market rate of 70-80% [3].
In many instances where encryption was observed, ransom notes with the naming pattern “README_[a-zA-Z0-9]{6}.txt” were written to affected devices. The content of these ransom notes threatened to release stolen confidential data via RansomHub’s DLS unless a ransom was paid. During these attacks, data exfiltration activity to external endpoints using the SSH protocol was observed. The external endpoints to which the data was transferred were found to coincide with servers previously associated with ShadowSyndicate activity.
Darktrace’s coverage of ShadowSyndicate and RansomHub
Darktrace’s Threat Research team identified high-confidence indicators of compromise (IoCs) linked to the ShadowSyndicate group deploying RansomHub. The investigation revealed four separate incidents impacting Darktrace customers across various sectors, including education, manufacturing, and social services. In the investigated cases, multiple stages of the kill chain were observed, starting with initial internal reconnaissance and leading to eventual file encryption and data exfiltration.
Attack Overview
Internal Reconnaissance
The first observed stage of ShadowSyndicate attacks involved devices making multiple internal connection attempts to other internal devices over key ports, suggesting network scanning and enumeration activity. In this initial phase of the attack, the threat actor gathers critical details and information by scanning the network for open ports that might be potentially exploitable. In cases observed by Darktrace affected devices were typically seen attempting to connect to other internal locations over TCP ports including 22, 445 and 3389.
C2 Communication and Data Exfiltration
In most of the RansomHub cases investigated by Darktrace, unusual connections to endpoints associated with Splashtop, a remote desktop access software, were observed briefly before outbound SSH connections were identified.
Following this, Darktrace detected outbound SSH connections to the external IP address 46.161.27[.]151 using WinSCP, an open-source SSH client for Windows used for secure file transfer. The Cybersecurity and Infrastructure Security Agency (CISA) identified this IP address as malicious and associated it with ShadowSyndicate’s C2 infrastructure [4]. During connections to this IP, multiple gigabytes of data were exfiltrated from customer networks via SSH.
Data exfiltration attempts were consistent across investigated cases; however, the method of egress varied from one attack to another, as one would expect with a RaaS strain being employed by different affiliates. In addition to transfers to ShadowSyndicate’s infrastructure, threat actors were also observed transferring data to the cloud storage and file transfer service, MEGA, via HTTP connections using the ‘rclone’ user agent – a command-line program used to manage files on cloud storage. In another case, data exfiltration activity occurred over port 443, utilizing SSL connections.
Lateral Movement
In investigated incidents, lateral movement activity began shortly after C2 communications were established. In one case, Darktrace identified the unusual use of a new administrative credential which was quickly followed up with multiple suspicious executable file writes to other internal devices on the network.
The filenames for this executable followed the regex naming convention “[a-zA-Z]{6}.exe”, with two observed examples being “bWqQUx.exe” and “sdtMfs.exe”.
Figure 1: Cyber AI Analyst Investigation Process for the SMB Writes of Suspicious Files to Multiple Devices' incident.
Additionally, script files such as “Defeat-Defender2.bat”, “Share.bat”, and “def.bat” were also seen written over SMB, suggesting that threat actors were trying to evade network defenses and detection by antivirus software like Microsoft Defender.
File Encryption
Among the three cases where file encryption activity was observed, file names were changed by adding an extension following the regex format “.[a-zA-Z0-9]{6}”. Ransom notes with a similar naming convention, “README_[a-zA-Z0-9]{6}.txt”, were written to each share. While the content of the ransom notes differed slightly in each case, most contained similar text. Clear indicators in the body of the ransom notes pointed to the use of RansomHub ransomware in these attacks. As is increasingly the case, threat actors employed double extortion tactics, threatening to leak confidential data if the ransom was not paid. Like most ransomware, RansomHub included TOR site links for communication between its "customer service team" and the target.
Figure 2: The graph shows the behavior of a device with encryption activity, using the “SMB Sustained Mimetype Conversion” and “Unusual Activity Events” metrics over three weeks.
Since Darktrace’s Autonomous Response capability was not enabled during the compromise, the ransomware attack succeeded in its objective. However, Darktrace’s Cyber AI Analyst provided comprehensive coverage of the kill chain, enabling the customer to quickly identify affected devices and initiate remediation.
Figure 3: Cyber AI Analyst panel showing the critical incidents of the affected device from one of the cases investigated.
In lieu of Autonomous Response being active on the networks, Darktrace was able to suggest a variety of manual response actions intended to contain the compromise and prevent further malicious activity. Had Autonomous Response been enabled at the time of the attack, these actions would have been quickly applied without any human interaction, potentially halting the ransomware attack earlier in the kill chain.
Figure 4: A list of suggested Autonomous Response actions on the affected devices."
Conclusion
The Darktrace Threat Research team has noted a surge in attacks by the ShadowSyndicate group using RansomHub’s RaaS of late. RaaS has become increasingly popular across the threat landscape due to its ease of access to malware and script execution. As more individual threat actors adopt RaaS, security teams are struggling to defend against the increasing number of opportunistic attacks.
For customers subscribed to Darktrace’s Security Operations Center (SOC) services, the Analyst team promptly investigated detections of the aforementioned unusual and anomalous activities in the initial infection phases. Multiple alerts were raised via Darktrace’s Managed Threat Detection to warn customers of active ransomware incidents. By emphasizing anomaly-based detection and response, Darktrace can effectively identify devices affected by ransomware and take action against emerging activity, minimizing disruption and impact on customer networks.
Credit to Kwa Qing Hong (Senior Cyber Analyst and Deputy Analyst Team Lead, Singapore) and Signe Zahark (Principal Cyber Analyst, Japan)
