Rapid7 assessed an intrusion disguised as Chaos ransomware to be a false-flag operation likely linked to MuddyWater, using Microsoft Teams social engineering, credential theft, and remote access tools instead of encryption. The campaign centered on ms_upd.exe and Game.exe, with infrastructure and a code-signing certificate connecting the activity to Iranian MOIS-affiliated tradecraft. #MuddyWater #Chaos #MicrosoftTeams #DWAgent #AnyDesk
Keypoints
- The intrusion initially looked like a Chaos ransomware incident, but analysis suggested a state-sponsored false flag operation.
- Moderate-confidence attribution linked the activity to MuddyWater, an Iranian APT associated with MOIS.
- Attackers used Microsoft Teams chats and screen-sharing to harvest credentials and manipulate MFA.
- Rather than encrypting files, the operators focused on persistence, lateral movement, and data exfiltration.
- Remote access tools including DWAgent and AnyDesk were used to maintain control of compromised systems.
- The custom payload chain included ms_upd.exe as a downloader and Game.exe as a RAT disguised as a Microsoft WebView2 application.
- Technical artifacts such as the âDonald Gayâ code-signing certificate and moonzonet[.]com C2 strengthened the MuddyWater link.
MITRE Techniques
- [T1566 ] Phishing (Spearphishing via Service) â Initial access was gained through Microsoft Teams messages and targeted social engineering (âthe TA engaged employees through external chat requestsâ).
- [T1059 ] Command and Scripting Interpreter â The attacker ran discovery and control commands such as ipconfig, whoami, and curl (âexecuted basic discovery commandsâ).
- [T1082 ] System Information Discovery â Host details were gathered from infected systems (âcollecting basic host information, including computer name, username, and domainâ).
- [T1016 ] System Network Configuration Discovery â Network configuration was enumerated using commands like ipconfig (âaccessed files related to the victimâs VPN configurationâ).
- [T1078 ] Valid Accounts â Harvested credentials were reused to authenticate to internal systems (âauthenticated to internal systems, including a Domain Controller, using multiple compromised accountsâ).
- [T1056 ] Input Capture â Victims were instructed to enter credentials into attacker-created text files (âenter credentials into locally created text filesâ).
- [T1556 ] Modify Authentication Process â MFA settings were altered to include attacker-controlled devices (âmodify MFA configurations to include attacker-controlled devicesâ).
- [T1021.001 ] Remote Services: RDP â Remote Desktop was used for access and movement (âestablished persistent remote access through RDP sessionsâ).
- [T1219 ] Remote Access Tools â DWAgent and AnyDesk were deployed for persistence and control (âestablish persistence using remote access tools such as DWAgent and AnyDeskâ).
- [T1543 ] Create or Modify System Process â DWAgent was installed as a service (âdwagsvc.exe â DWAgent servicedâ).
- [T1055 ] Process Injection â A renamed python binary was used to inject code into suspended processes (âthe groupâs signature use of pythonw.exe to inject code into suspended processesâ).
- [T1105 ] Ingress Tool Transfer â Additional payloads were downloaded with curl (âdownload additional payloads using curlâ).
- [T1041 ] Exfiltration Over C2 Channel â Data was exfiltrated to external infrastructure (âthe TA exfiltrated data from the compromised environmentâ).
- [T1027 ] Obfuscated Files or Information â The RAT used XOR encoding and encrypted configuration data (âXOR encoding ⌠to hide specific anti-analysis stringsâ).
- [T1497 ] Virtualization/Sandbox Evasion â Game.exe checked for sandbox and VM artifacts (âsearch for known analysis-related DLLsâ).
- [T1622 ] Debugger Evasion â The malware included anti-analysis checks to avoid inspection (âanti analysis techniquesâ).
- [T1071 ] Application Layer Protocol â C2 traffic used web-style endpoints over HTTP/S (âpolling /index.php every 60 secondsâ).
- [T1573 ] Encrypted Channel â The RAT used encrypted C2 communication (âdecrypts its configuration using AES-256-GCMâ).
- [T1133 ] External Remote Services â Compromised accounts were used to access VPN/external remote services (âusing compromised accountsâ).
- [T1087 ] Account Discovery â User/account information was enumerated (âgathering host information, including computer name, usernameâ).
- [T1018 ] Remote System Discovery â Multiple systems were enumerated and moved through (âmove between systemsâ).
Indicators of Compromise
- [SHA256 ] Malware samples and related payloads â 24857fe82f454719cd18bcbe19b0cfa5387bee1022008b7f5f3a8be9f05e4d14, 1319d474d19eb386841732c728acf0c5fe64aa135101c6ceee1bd0369ecf97b6, and other 4 hashes
- [File names ] Droppers, RATs, and support binaries observed during the intrusion â ms_upd.exe, Game.exe, and other 5 file names
- [Domain ] Command-and-control and phishing infrastructure â moonzonet[.]com, uploadfiler[.]com
- [URL ] Credential harvesting and downloader locations â hxxps[://]adm-pulse[.]com/verify.php, hxxp[://]172.86.126[.]208:443/ms_upd.exe
- [IP addresses ] Malicious infrastructure and Teams-related source IPs â 77.110.107[.]235, 172.86.126[.]208, and other 2 IPs
- [Onion service ] Chaos ransomware leak site and negotiation portal â hptqq2o2qjva7lcaaq67w36jihzivkaitkexorauw7b2yul2z6zozpqd[.]onion
- [Certificate details ] Signing identity used across the malware chain â Donald Gay, Microsoft ID Verified CS AOC CA 02
- [Mutex ] Single-instance enforcement in Game.exe â ATTRIBUTES_ObjectKernel
Read more: https://www.rapid7.com/blog/post/tr-muddying-tracks-state-sponsored-shadow-behind-chaos-ransomware