Momibot Worm – Spreading in the Wild (March 18, 2011)


SonicWALL UTM Research team received reports of a new variant of Momibot worm propagating in the wild. This worm propagates through emails, network and removable drives.

Process of Infection:

An unsuspecting user may receive an email with the malware attachment.

From: {user}
Subject: nake pics as you’ve requested
Attachment: (59.3KB)



Once the user opens and executes the attachment, it will do the following:

Drops a copy of itself:

  • %System%{random filename in %System%}{random letter}.exe – [ detected as GAV: Momibot.B_4 (Trojan) ]
  • %System%{random filename}.dat – [ Data File ]

Registry Changes

Adds the following AutoStart registry entries to ensure that the malware runs on every system startup.

  • HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRun
    Value: Win32Update
    Data: “C:WINDOWSSystem32{random filename in %System%}{random letter}.exe”
  • HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersionRunServices
    Value: Win32Update
    Data: “C:WINDOWSSystem32{random filename in %System%}{random letter}.exe”
  • HKEY_LOCAL_MACHINESoftwareMicrosoftOLE
    Value: Win32Update
    Data: “C:WINDOWSSystem32{random filename in %System%}{random letter}.exe”
  • HKEY_LOCAL_MACHINESystemCurrentControlsetControlLsa
    Value: Win32Update
    Data: “C:WINDOWSSystem32{random filename in %System%}{random letter}.exe”

Adds the following registry entries to install the malware as a Service. Service name was derived from appending two existing services already installed in the system.

  • HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesTermServiceRSVP
    Value: ImagePath
    Data: “C:WINDOWSSystem32{random filename in %System%}{random letter}.exe”


Creates this mutex to ensure only a single instance is running in the memory.

  • 9LZZ1TXjZ5NHrnf71f

Command & Control (C&C) Server connection:

Upon successful installation, it tries to connect to a remote server to receive further instruction:

  • http://9{REMOVED}5.174

This worm will also join the following IRC Channel to receive instruction:

  • Port: 6667
  • IRC Channel: #AllNiteCafe

Backdoor Functionality:

  • Update itself
  • Remove itself
  • Download and execute files
  • Gather system information

SonicWALL Gateway AntiVirus provides protection against this worm via the following signatures:

GAV: Momibot.B_4 (Trojan)

Security News
The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.