DISGOMOJI: The Emoji-Driven Linux Malware

Research Wing
Research Wing
Innovation and Research
PUBLISHED ON
Jun 29, 2024
10

Executive Summary:

New Linux malware has been discovered by a cybersecurity firm Volexity, and this new strain of malware is being referred to as DISGOMOJI. A Pakistan-based threat actor alias ‘UTA0137’ has been identified as having espionage aims, with its primary focus on Indian government entities.  Like other common forms of backdoors and botnets involved in different types of cyberattacks, DISGOMOJI, the malware  allows the use of commands to capture screenshots, search for files to steal, spread additional payloads, and transfer files. DISGOMOJI  uses Discord (messaging service)  for Command & Control (C2)  and uses emojis  for C2 communication. This malware targets Linux operating systems.

The DISCOMOJI Malware:  

  • The DISGOMOJI malware opens a specific channel in a Discord server and every new channel corresponds to a new victim. This means that the attacker can communicate with the victim one at a time.
  • This particular malware connects with the attacker-controlled Discord server using Emoji, a form of relay protocol. The attacker provides unique emojis as instructions, and the malware uses emojis as a feedback to the subsequent command status.
  • For instance, the ‘camera with flash’ emoji is used to screenshots the device of the victim or to steal, the ‘fox’ emoji cracks all Firefox profiles, and the ‘skull’ emoji kills the malware process.
  • This C2 communication is done using emojis to ensure messaging between infected contacts, and it is almost impossible for Discord to shut down the malware as it can always change the account details of Discord it is using once the maliciou server is blocked.
  • The malware also has capabilities aside from the emoji-based C2 such as network probing, tunneling, and data theft that are needed to help the UTA0137 threat actor in achieving its espionage goals.

Specific emojis used for different commands by UTA0137:

  • Camera with Flash (📸): Captures a picture of the target device’s screen as per the victim’s directions.
  • Backhand Index Pointing Down (👇): Extracts files from the targeted device and sends them to the command channel in the form of attachments.
  • Backhand Index Pointing Right (👉): This process involves sending a file found on the victim’s device to another web-hosted file storage service known as Oshi or oshi[. ]at.
  • Backhand Index Pointing Left (👈): Sends a file from the victim’s device to transfer[. ]sh, which is an online service for sharing files on the Internet.
  • Fire (🔥): Finds and transmits all files with certain extensions that exist on the victim’s device, such as *. txt, *. doc, *. xls, *. pdf, *. ppt, *. rtf, *. log, *. cfg, *. dat, *. db, *. mdb, *. odb, *. sql, *. json, *. xml, *. php, *. asp, *. pl, *. sh, *. py, *. ino, *. cpp, *. java,
  • Fox (🦊): This works by compressing all Firefox related profiles in the affected device. 
  • Skull (💀): Kills the malware process in windows using ‘os. Exit()’
  • Man Running (🏃‍♂️):  Execute a command on a victim’s device. This command receives an argument, which is the command to execute.
  • Index Pointing up (👆) : Upload a file to the victim's device. The file to upload is attached along with this emoji

Analysis:   

The analysis was carried out for one of the indicator of compromised SHA-256 hash file-  C981aa1f05adf030bacffc0e279cf9dc93cef877f7bce33ee27e9296363cf002.

It is found that most of the vendors have marked the file as trojan in virustotal and the graph explains the malicious nature of the contacted domains and IPs.

Graphical representation of the above analysis

Discord & C2 Communication  for UTA0137:

  • Stealthiness: Discord is a well-known messaging platform used for different purposes, which means that sending any messages or files on the server should not attract suspicion. Such stealthiness makes it possible for UTA0137 to remain dormant for greater periods before launching an attack.
  • Customization: UTA0137 connected to Discord is able to create specific channels for distinct victims on the server. Such a framework allows the attackers to communicate with each of the victims individually to make a process more accurate and efficient.
  • Emoji-based protocol: For C2 communication, emojis really complicates the attempt that Discord might make to interfere with the operations of the malware. In case the malicious server gets banned, malware could easily be recovered, especially by using the Discord credentials from the C2 server.
  • Persistence: The malware, as stated above, has the ability to perpetually exist to hack the system and withstand rebooting of systems so that the virus can continue to operate without being detected by the owner of the hacked system.
  • Advanced capabilities: Other features of DISGOMOJI are the Network Map using Nmap scanner, network tunneling through Chisel and Ligolo and Data Exfiltration by File Sharing services. These capabilities thus help in aiding the espionage goals of UTA0137.
  • Social engineering: The virus and the trojan can show the pop-up windows and prompt messages, for example the fake update for firefox and similar applications, where the user can be tricked into inputting the password.
  • Dynamic credential fetching: The malware does not write the hardcoded values of the credentials in order to connect it to the discord server. This also inconveniences analysts as they are unable to easily locate the position of the C2 server.
  • Bogus informational and error messages: They never show any real information or errors because they do not want one to decipher the malicious behavior easily.

Recommendations to mitigate the risk of UTA0137:

  • Regularly Update Software and Firmware: It is essential to regularly update all the application software and firmware of different devices, particularly, routers, to prevent hackers from exploiting the discovered and disclosed flaws. This includes fixing bugs such as CVE-2024-3080 and CVE-2024-3912 on ASUS routers, which basically entails solving a set of problems.
  • Implement Multi-Factor Authentication: There are statistics that show how often user accounts are attacked, it is important to incorporate multi-factor authentication to further secure the accounts.
  • Deploy Advanced Malware Protection: Provide robust guard that will help the user recognize and prevent the execution of the DISGOMOJI malware and similar threats.
  • Enhance Network Segmentation: Utilize stringent network isolation mechanisms that seek to compartmentalize the key systems and data from the rest of the network in order to minimize the attack exposure.
  • Monitor Network Activity: Scanning Network hour to hour for identifying and handling the security breach and the tools such as Nmap, Chisel, Ligolo etc can be used.
  • Utilize Threat Intelligence: To leverage advanced threats intelligence which will help you acquire knowledge on previous threats and vulnerabilities and take informed actions.
  • Secure Communication Channels: Mitigate the problem of the leakage of developers’ credentials and ways of engaging with the discord through loss of contact to prevent abusing attacks or gaining control over Discord as an attack vector.
  • Enforce Access Control: Regularly review and update the user authentication processes by adopting stricter access control measures that will allow only the right personnel to access the right systems and information.
  • Conduct Regular Security Audits: It is important to engage in security audits periodically in an effort to check some of the weaknesses present within the network or systems.
  • Implement Incident Response Plan: Conduct a risk assessment, based on that design and establish an efficient incident response kit that helps in the early identification, isolation, and management of security breaches.
  • Educate Users: Educate users on cybersecurity hygiene, opportunities to strengthen affinity with the University, and conduct retraining on threats like phishing and social engineering.

Conclusion:

The new threat actor named UTA0137 from Pakistan who was utilizing DISGOMOJI malware to attack Indian government institutions using embedded emojis with a command line through the Discord app was discovered by Volexity. It has the capability to exfiltrate and aims to steal the data of government entities. The UTA0137 was continuously improved over time to permanently communicate with victims. It underlines the necessity of having strong protection from viruses and hacker attacks, using secure passwords and unique codes every time, updating the software more often and having high-level anti-malware tools. Organizations can minimize advanced threats, the likes of DISGOMOJI and protect sensitive data by improving network segmentation, continuous monitoring of activities, and users’ awareness.

References:

https://otx.alienvault.com/pulse/66712446e23b1d14e4f293eb

https://thehackernews.com/2024/06/pakistani-hackers-use-disgomoji-malware.html?m=1

https://cybernews.com/news/hackers-using-emojis-to-command-malware/

https://www.blackhatethicalhacking.com/news/disgomoji-new-linux-malware-uses-emojis-for-command-execution/

https://www.volexity.com/blog/2024/06/13/disgomoji-malware-used-to-target-indian-government/

PUBLISHED ON
Jun 29, 2024
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