abiyq

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Victims will see .abiyq appended as a secondary extension after the original file extension (e.g., Budget2024.xlsx.abiyq, Family.jpg.abiyq, db_backup.mdf.abiyq).
  • Renaming Convention: The ransomware does not use a prefix token or a victim ID in the filename itself; only the double-extension pattern is employed, making it immediately distinguishable from other ransomware families.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: The first public sightings of the .abiyq strain occurred late July 2023, with a significant spike in late-August 2023 when cybersecurity vendors began tracking it as a possible branch of the STOP/Djvu family (based on code overlap).

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Cracked-Software Installers – Widely distributed via torrent indexes and “free download” sites that bundle the malicious dropper with Adobe cracks, game cheats, or keygen utilities.
  2. Malvertising Chains – Drive-by downloads triggered by deceptive ad campaigns that redirect to RIG, SocGholish, or fake-update JavaScript frameworks; the payload hashes vary every 12-24 h to evade static signatures.
  3. Phishing E-mails – ZIP attachments with double-extension files (e.g., Invoice-0215.pdf.exe) that launch PowerShell to download the current .abiyq loader.
  4. Weak RDP / SMB Credentials – Automated brute-force tools attempt admin:***portal123, *BourneStrong!2023*, and several other trending credentials; lateral movement afterward leverages WMI and scheduled tasks.
  5. Fake Software Updates – Pop-ups that mimic Chrome, Firefox, Microsoft Update, or even “Windows 11 Security Hotfix.” Clicking installs the downloader which in turn retrieves the .abiyq executable.

Remediation & Recovery Strategies:

1. Prevention

Secure your environment against .abiyq:

  • Block all macro-enabled documents via Group Policy (only allow digitally signed macros from your PKI).
  • Disable legacy SMBv1 across every Windows host; ensure SMB signing is enforced.
  • Enforce strong unique local-admin passwords using Microsoft LAPS and high-complexity user passwords (> 14 characters).
  • Segment networks so that even if a desktop is infected, lateral movement to file servers is impossible.
  • Patch routinely—especially Chrome, Java, Acrobat, .NET, VPN appliances, Exchange (ESU), and any exposed RDP gateways.
  • Maintain an offline/3-2-1 backup program with no writable shares during backup windows.
  • Deploy an EDR or NGAV solution that can block process injection and PowerShell obfuscation (T1055 + T1059 use cases).
  • Restrict users from running binaries located in %TEMP% (%AppData%\Local\Temp\*.exe) via Applocker rules.

2. Removal

Clean the infection in this order:

  1. Disconnect the infected machine from the network (both wired Wi-Fi and any VPN).
  2. Preserve volatile evidence (memory capture if forensics is needed).
  3. Boot into Safe Mode with Networking or use an offline rescue USB (Kaspersky / Bitdefender / ESET).
  4. Run the latest offline AV definition file; look for winupdate.exe, abiyq.exe, or randomly-named 8-char executables in C:\Users\<user>\AppData\Roaming and delete.
  5. Clean scheduled tasks created under Task Scheduler -> Task Scheduler Library -> Microsoft -> Windows -> SystemRestore (names like “serviceauto” or “msdnstat”).
  6. Remove persistence registry keys: 
   HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
   HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell
  1. Full scan with reputable AV/EDR; reboot and rescan to confirm no resurrection.
  2. Change all local and domain credentials used on the host/found in the browsers.

3. File Decryption & Recovery

  • Offline Key Cases:
    If your infection is from an August 2023 or later variant and a fixed offline key has been captured by security researchers, you can use Emsisoft STOP/Djvu Decrypter v1.0.0.0+ (download only from emsisoft.com/decrypt-stop-djvu). Feed the tool the file pair (original + encrypted) and the ransom note (_readme.txt) to test decryption.

  • New/Online Key Cases:
    If the decrypter reports “Online key needed,” the per-victim key lives only on the C&C server; brute-force or generic decryptors will not work. Your options are:

  1. Restore from offline backups staging prior to infection.
  2. Leverage Windows shadow copies (vssadmin list shadows) or backup agent images if shadow copy was not erased.
  3. Restore OneDrive / SharePoint / Google Drive file versions (they are typically unaffected).
  4. Pay ransom: Not recommended—payment guarantees nothing, encourages crime, and doubles the financial loss.

Critical patches & tools to deploy right now:

  • KB5019162 (Windows 10 22H2) + August 2023 cumulative rollups.
  • Chrome 128 or newer / Firefox 128.
  • Enable Controlled Folder Access (Windows Defender) on servers.
  • Emsisoft Anti-Malware or Kaspersky Emergency Disk as on-demand scanners.

4. Other Critical Information

  • Evasion Tactics: .abiyq is packed with Themida and hides behind “trusted” host processes (dllhost, svchost) via classic process hollowing. The ransom note drops in every folder as _readme.txt, demanding $490 in BTC (doubles to $980 after 72 h);
    Fake support e-mails ([email protected], [email protected]) do not respond after payment in a majority of observed cases.
  • Language Targeting: Campaigns are localized in Russian via Slavic forums and in English via Reddit “crack request” posts.
  • Conti-style takedown of the payout infrastructure is unlikely (STOP/Djvu affiliate model is highly distributed).
  • Historical Impact: STOP/Djvu derivatives (of which .abiyq is a member) remain the №1 cause worldwide of consumer-PC crypto-ransom; sensor data from abuse.ch shows >110 k unique SHA256s linked to the family per month.

Stay disciplined—adequate backups, patch cadence, and controlled folder access will render .abiyq harmless to your organization.