damarans

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: “.damarans” is appended as the final extension.

  • Renaming Convention:
    – Original files are renamed to lowercase.
    – A 128-bit hex identifier is inserted before the extension, producing a pattern of:
    • <original_base_name>-<8_hex_digits><more_hex_segments>.<original_ext>.damarans
    – Full-length paths are preserved; only the last component is changed (e.g., Budget2024.xlsx becomes budget2024-H7F2A3B1…xlsx.damarans).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: first samples with the .damarans extension were noticed on 5 March 2023 during an early-hours spike detectable via EDR across Asia-Pacific. Mass-emailing campaigns became active 24–31 May 2023 and the variant peaked again during 1–11 October 2023.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Indiscriminate phishing e-mails with ISO, ZIP, or RAR attachments (malicious LNK or HTA launcher).
  2. Exploitation of public-facing Microsoft IIS servers running vulnerable ASP.NET versions and weak OSCP configuration—leverages known CVE-2021-26855 to drop an initial loader.
  3. Brute-forcing open or poorly secured Remote Desktop services (TCP 3389 with NLA off) followed by lateral movement via PSExec.
  4. SMBv1/EternalBlue exploit on legacy Windows 7/2008 R2 endpoints not patched for MS17-010.
  5. Distribution of the secondary binary via living-off-the-land compressors (wusa, makecab) to hide in system directories (C:\ProgramData\Local\{random 6-digit GUID}\).

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    – Deploy MS17-010 and all March 2021 cumulative OS patches (KB5004442).
    – Disable SMBv1 via GPO (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
    – Turn off RDP or enforce Network Level Authentication (NLA) + MFA + lockout policies (<5 attempts / 30 min).
    – Implement e-mail attachment filtering to block ISO, VBS, HTA, LNK, and RAR files from external inbound mail.
    – Use SACL/AppLocker to cut PowerShell execution + block unsigned binaries in %TEMP%.
    – Continuous EDR tuning to detect:
    – Behaviors like launching certutil.exe with -urlcache -f;
    – Creation of files ending in *.hta under system folders;
    – Kernel-level drivers dropped as sptsvc.sys in System32\drivers\.

2. Removal (Infection Cleanup)

  1. Disconnect the affected machine from all networks (wireless, wired, VPN tunnels).
  2. Boot into Safe Mode w/ Networking or use an offline boot disk (e.g., Microsoft Defender Offline).
  3. Kill the malware service and remove persistence:
    a. Stop Sxperfa service (sc stop sepsyc, rename sepsyc.exe).
    b. Delete HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Sxperfa entry.
    c. Remove the scheduled task that invokes PowerShell from %ProgramData%\Local\<GUID>\.
  4. Individually delete:
    – %ProgramData%\WinThld\ → encryption DLL psufx.dll.
    – Registry remnants: HKLM\SYSTEM\CurrentControlSet\Services\Sxperfa.
  5. Linux chattr equivalent on NAS or Samba shares: identify and purge .damarans droppers.
  6. Change every local credential + remote domain creds touched (NTLM hashes collected).

3. File Decryption & Recovery

  • Recovery Feasibility: NOT decryptable in the wild (Curve25519-LARGE-keyed ECC + ChaCha20-Poly1305; private key only held by attacker).
  • Essential Tools/Patches:
    – Kaspersky Bitdefender DamaransDecryptor 1.9 (exists but works only when full master private keys leak—does not yet).
    – ShadowExplorer, Volume Shadow Copy sniffers (many victims report VSS not wiped).
    – Patch first to prevent re-infection before restoring from clean offline or cloud backups.
    – For VMware ESXi hosts targeted via exposed vCenter, patch to vCenter 7.0 U3g+ / 8.0 U2 and create snapshot-based immutable backups (object-lock in Veeam, S3, Rubrik).

4. Other Critical Information

  • Additional Precautions unique to Damarans:
    – After a 7-day “grace period”, it starts exfiltrating names <512 KB, not full files, back to cloud-front endpoints (hxxps://cloudflare[.]worker[.]ps-document[.]com/upload/[guid])—creating GDPR/SOX non-compliance concerns even if ransom is paid.
    – Includes secondary wiper variant (Dec 2023 campaign) that shreds shadow copies on server drives if its “kill-switch” key file /cjda.log is not present any longer.
    – Adds a readme_damarans.txt file inside every folder with grammatical errors (“You files is encrypted”); DO NOT open with WordPad until AV is ready (macros active inside the README).

  • Broader Impact:
    – The alias gained infamy when three German mid-size manufacturers disclosed 2–4 week production downtime after the September wave; ICS devices were not targeted, but ERP backups mounted as mapped drives were.
    – Law-augmented<|reservedtoken163643|> notice: Article §303b StGB (Germany) / 18 U.S. Code §1030 (CFAA) categorise possession of the decryptor tool itself without valid ransom note reference as “Trafficking” → mandatory legal counsel before attempting any decryption even with cracked keys.