Ako ransomware demands $3000. Operators hide behind tOr.

The SonicWall Capture Labs Threat Research Team have recently come across a new variant of Ako ransomware. The malware spreads via spam email and shares similarities to MedusaLocker. This has lead many to believe that the malware is a variant of MedusaReborn. However, the operators have reportedly denied this claim and state that Ako is their own creation. The malware demands $3000 USD in Bitcoin for file retrieval. The operators run a website hosted behind tOr to facilitate file decryption for its victims.

Infection Cycle:

Upon infection, the malware encrypts files and appends <.random{6}> to their filenames. eg. finance.docx.C564Ec

The following files are dropped into directories where files were encrypted:

  • ako-readme.txt
  • id.key

ako-readme.txt contains the following text:

id.key contains the public key used to encrypt files.

During the encryption process, the following file types are ignored:

  • .exe ,. dll, .sys, .ini, .lnk, .key, .rdp

Folders containing the following strings are also skipped:

  • Appdata
  • Program files
  • Program Files (x86)
  • Appdata
  • boot
  • Perflogs
  • Programdata
  • Google
  • Intel
  • Microsoft
  • Application data
  • Tor browser
  • Windows

Each encrypted file is given the following infection marker (CECAEFBE):

The following keys are added to the registry:

  • HKEY_CURRENT_USERSoftwareakocfg aid “.<random{6}>”
  • HKEY_USERSS-1-5-21-3032013890-123666948-3153623785-1001Softwareakocfg aid “.<random{6}>”

The following commands are executed to delete shadow copies of files and to disable any possibility of system recovery and repair:

  • vssadmin.exe Delete Shadows / All / Quiet
  • bcdedit.exe / set {default} recoveryenabled No
  • bcdedit.exe / set {default} bootstatuspolicy ignoreallfailures
  • wbadmin DELETE SYSTEMSTATEBACKUP
  • wbadmin DELETE SYSTEMSTATEBACKUP -deleteOldest
  • wmic.exe SHADOWCOPY / nointeractive

The ransom note contains the following tOr address:

  • http://kwvhrdibgmmpkhkidrby4mccwqpds5za6uo2thcw5gz75qncv7rbhyad.onion/U0T9NR3RCU3PNABN

The address leads to the following site hosted on the tOr network:

After entering the unique key from the ransom note, the following page is presented which states that 0.2932 BTC (approx $3000 USD at this time) is required to restore files:

Activity recorded for the supplied BTC address (1Ag76nHNv1mPUf3Qki1EnoHgV4Cbt6dLft) suggests that the operators may have been successful in their endeavours:

SonicWall Capture Labs provides protection against this threat via the following signature:

  • GAV: Ako.RSM (Trojan)

This threat is also detected by SonicWALL Capture ATP w/RTDMI and the Capture Client endpoint solutions.

** Optrics Inc. is an Registered SonicWall partner


The original article can be found here:

https://securitynews.sonicwall.com/xmlpost/ako-ransomware-demands-3000-operators-hide-behind-tor/

About the Author: Shannon Lewis

Leave a Reply