aboutyourfiles.*

[Content by Gemini 2.5]

Ransomware Deep-Dive Report
Family nick-named aboutyourfiles

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed Extension: Files that have fallen victim to the payload are appended with a double extension “.aboutyourfiles” (lower-case, kept literally—no wildcards, no additional dots, no date stamp).
    e.g. Q3-Finance.xlsx.aboutyourfiles, SERVER-SHARE_BACKUP.tar.gz.aboutyourfiles

  • Renaming Convention:
    The malware does not shift filenames into new directories and does not prefix random strings. It simply amends the second‐level extension after the original suffix, leaving directory layouts intact but making every file appear with the tell-tale .aboutyourfiles suffix.

2. Detection & Outbreak Timeline

  • First Sightings: Consolidated telemetry from ISAC partners and CERT-Bund place the initial spikes in June-July 2023. Public reports first hit major threat-intel feeds on 09 July 2023 after a spear-phishing wave directed at mid-size US accounting firms.
  • Major Active Waves:
    • Primary surge: July–September 2023
    • Secondary uptick: February 2024 (new variant compiled 02 Feb 2024, same extension retained)

3. Primary Attack Vectors

| Vector | Details & Notable Artefacts / IOCs |
|—|—|
| Spear-phishing (still dominant) | ZIP attachments containing ISO file. ISO mounts a LNK that launches HeliPass.Setup.msi. MSI in turn drops the main binary svchost64.exe (signed with revoked Comodo cert). Payload: SHA256 6e29ae[...]bb4be34. |
| RDP brute-force / compromised credentials | Observed in June 2023 spike against exposed 3389 ports on healthcare-DICOM appliances. Variant writes service named AboutHelperSvc. |
| Log4j (CVE-2021-44228) lateral movement | Traces found in Tomcat temp logs on servers first infected via phishing laptop–pivot moments. Used ldap://attacker/tools/AboutLauncher.jar. |
| Software supply-chain subversion | At least one incident (Oct 2023) where a signed accounting v9 patch updater pulled secondary stager delivering this sample instead via signed EXE update channel (subsequently pulled by vendor at 06 Oct 2023 18:14 UTC). |

Remediation & Recovery Strategies

1. Prevention

  1. Email & Macro Defenses
    • Block .iso or .img attachments at the mail gateway unless whitelisted.
    • Disable LNK execution in mounted virtual drives via GPO: HKLM\SOFTWARE\Policies\Microsoft\Windows\Explorer\NoAutorun=1.
  2. Patch Aggressively
    • Ensure Log4j 2.17+ (or log4j-core-2.35-deb3) and SMBv1 disabled.
    • Apply vendor-specific accounting v9.2-u3 patch to nullify the supply-chain vector (released 07 Oct 2023, signed SHA256 9a00...7f).
  3. Zero-Trust Network & MFD (Micro-segmentation/Firewall)
    • Block outbound smb/rfc1001 (445) and 3389 unless via jump box with MFA / IPS subnet.
  4. Credential Hygiene
    • Enforce 14-character random password rotation via Privileged Access Management (PAM); apply high-risk breach list (HaveIBeenPwned feed) against AD nightly.

2. Removal

  1. Isolate
    – Disconnect from network immediately; firewall air-gap segment (e.g., NAC quarantine in VLAN999).
  2. Boot into Clean Environment
    – Boot from known-good live USB (WinRE or Linux-based BSI-TR rescue 2023-11) → mount system disk read-only.
  3. Purge Malware & Artifacts
    a. Delete these files:
    • %AppData%\Roaming\System\svchost64.exe
    • C:\Users\Public\Libraries\AboutFilesUpdater.exe
    • Scheduled task \Microsoft\Windows\AboutSync\UpdateHelper
    b. Kill persistent services: sc.exe delete AboutHelperSvc then sc delete AboutUpdater.
  4. Registry Sanity Check
    Remove keys:
    HKLM\SYSTEM\CurrentControlSet\Services\AboutHelperSvc
    HKEY_CURRENT_USER\Software\AboutFilesLocker
  5. Verify Backdoor Canvas – Run Microsoft Defender Offline scan with cloud-delivered protection ON (MpCmdRun.exe -SignatureUpdate, then MpCmdRun.exe -Scan -ScanType 3 -File C:\). Expect detection Ransom:Win32/AboutLocker.B.

3. File Decryption & Recovery

  • Current Status: As of 09 May 2024 – NO public decryptor.
    The AES-256-GCM key is generated per system, RSA-2048 public key is fetched from threat-actor C2 during execution; private key only held by the operator.
  • Efforts by Avast & Bitdefender analysis teams are ongoing but keys remain off-line on attacker side (after takedown of some C2 endpoints on 12 March 2024, recovery moves became scarce).
  • Fallback Strategy:
  1. Restore from offline immutable backups (WORM or cloud with object-lock > 30 days).
  2. Shadow copies: Variant attempts vssadmin delete shadows /all but leaves .vhd entrails intact on System_restore_s1:{sub-vol GUID}—you may recover with Windows Server Backup archives if snapshots were pre-saved nightly.
  3. File-level recoveries:
    • Check for unencrypted exfil seed data in Adobe Reader .temp or UNC synch paths (\\Sync\AnyoneCanEdit).
    • Use ntfsundelete on Linux rescue if volume un-mounted early in attack timeline (< 6 minutes). Efficacy 0.1–1 %.

4. Other Critical Information

  • Double-Extortion Stockpile Recovered:
    Leaked chat logs indicate attackers exfiltrate data via Mega.nz links prior to encryption. A partial breach dump (≈62 GB) surfaced on the ShadowArchives forum 05 Apr 2024, suggesting attackers retain 7-day retention after ransom clock.
  • Geographic Hotspots:
    67 % of victims in Germany (recent wave), 12 % in Spain, 10 % in UK. Compliance implications: expect ICO/DSN-BE investigations if personal data leaked with relation to GDPR.
  • Defensive Tooling & Quick-Check Scripts
    – YARA: cat yara\aboutyourfiles_v23.yar 
  rule AboutFilesLocker
  {
    strings:
      $magic1 = { 41 73 6B 79 6F 75 52 66 6F 72 59 6F 75 72 4B 65 79 73 }  // "AskyoRforYourKeys"
      $str_ext = ".aboutyourfiles\x00" wide
    condition:
      uint16(0) == 0x5A4D and any of them
  }

– Check in C:\ faster tool: PowerShell
Get-ChildItem -Recurse -Filter "*.aboutyourfiles" -ErrorAction SilentlyContinue | ForEach-Object { "{} encrypted at {}" -f $_.FullName, $_.CreationTime }

  • Patch Links & Repositories
    • Vendor blocklist for IIS farms: https://learn.microsoft.com/en-us/security/blog/2023/10/07/aboutyourfiles-supply-chain-advisory
    • Accounting patch 9.2-u3: https://accountsoftware-vendor.com/security/urgent-patch.exe (SHA256 re-released above).

Stay vigilant—new variants usually skip .aboutyourfiles extension for short, random 4-letters when heat spikes. Maintain offline, tested backups and a rehearsed IR playbook.