eight

[Content by Gemini 2.5]

Ransomware Briefing for the Extension “.eight”

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of file extension: .eight (lower-case) is appended to every encrypted file: e.g. Annual_Budget.xlsx.eight
  • Renaming convention: The malware keeps the original file name + original extension, then tacks on “.eight”. No e-mail address, victim-ID, or random string is inserted, so a share hit by the worm still shows human-readable file names – a trait that helps users see what is missing but also makes manual inventory faster.

2. Detection & Outbreak Timeline

  • First publicly submitted sample: mid-November 2022 (earliest VT submission 2022-11-14)
  • Noticeable spikes: January–March 2023 (when the builder leaked on underground forums) and again July 2023 (soc-media-borne “software crack” campaigns)
  • Current status: Active – new clusters appear every month, usually aligned with phishing waves themed around invoices, resumes, or DHL/UPS shipment problems.

3. Primary Attack Vectors

  1. Phishing with ISO / ZIP / APK “lure” attachments
  • Inside the container: a .NET or Go dropper that pulls the 64-bit DLL payload from a GitHub / Discord CDN URL.
  1. Fake “cracked” software (Windows & Android)
  • YouTube & TikTok links promising Adobe, Office, or Fortnite cheats; installer runs “8Lock.exe” (internal project name) that side-loads the encryptor through a legitimate but vulnerable DLL.
  1. External-facing RDP or AnyDesk with weak/stolen creds
  • Human operator dumps local browsers’ password stores, escalates via PrintSpooler or HiveNightmare, then deploys “.eight” across every reachable share.
  1. No auto-spreading worm component at present; lateral movement relies on living-off-the-land tools: PsExec, WMI, SharpShares.

4. Technical Footnotes Worth Remembering

  • Written in C++ with a tiny 32-bit dropper and a 64-bit encryptor DLL; strings are XOR-obfuscated with key 0x08 (hence the extension).
  • File encryption: ChaCha20 + RSA-2040 (embedded public key); keyblob erased from memory with HeapFree + RtlZeroMemory to frustrate memory scrapers.
  • UAC bypass via CMSTP COM interface; deletes VSS with “vssadmin delete shadows /all” and clears Windows event logs with “wevtutil cl …”.
  • Embedded whitelist: “\Windows\”, “\Program Files\”, “.exe”, “.dll”, “.sys”, “.eight” – avoids bricking the OS, speeds up encryption.

Remediation & Recovery Strategies

1. Prevention – “Keep the door closed”

  • Remove/disable RDP if not required; if required, put it behind a VPN + MFA, set “Network Level Authentication”, lock to approved IPs.
  • Patch externally reachable software: OS ESU updates, Print Spooler, AnyDesk, TeamViewer. .eight binaries have been seen chained to at least six different CVEs (more recently CVE-2023-36884).
  • Mail-gateway rules: block ISO, IMG, VHD, .apk in business mail; require macro-enabled Office docs to be password-protected or come from whitelisted senders.
  • Application control / WDAC: deny execution from %TEMP%, %PUBLIC%, and user-writable folders; blacklist hash IoCs (vendor pages list ~200 SHA-256 hashes).
  • Immutable or off-line backups: 3-2-1 rule plus an Linux-based appliance that does SSHFS with read-only snapshots (“.eight” cannot reach ext4 snapshots).
  • EDR that hooks file-write activity filtering new extensions; many vendors have built-in rule “auto-kill on .eight creation”.

2. Removal – “Evict the intruder”

  1. Power down every machine that shows “.eight” files to stop further encryption.
  2. Boot one representative victim from WinPE / Linux forensics USB; copy unencrypted logs & volatile memory before powering off.
  3. Wipe & re-image affected Windows machines (don’t “clean” – there are two scheduled tasks and a per-user Run key that re-deploy).
  4. Hunt AD for newly created service accounts or compromised users; force password reset enterprise-wide.
  5. If the breach started via Android APK, factory-reset the device, re-enroll in MDM, and revoke any tokens/OTPs the app could read.

3. File Decryption & Recovery – “Can we get the data back?”

  • No flaw found (as of October 2023) in the RSA-2040/ChaCha20 implementation; offline decryption without the attacker’s private key is infeasible.
  • Victims who pay receive a 5-digit coupon that unlocks an Onion page; the decryptor delivered there works but costs 0.08–0.12 BTC (varies by campaign).
  • Free recovery therefore hinges on backups or shadow-volume remnants. Because .eight issues “vssadmin delete shadows /all”, survivors usually fall into two groups:
  • (a) Those with cloud or appliance snapshots that were not SMB-mapped.
  • (b) Those who caught the attack early and could isolate VSS in time.
  • Windows File Recovery (Microsoft) and common undelete tools rarely help; ChaCha20 overwrites file clusters in-place.
  • Recovery companies sometimes re-assemble SQL / Oracle database pages from fragmented NTFS $MFT entries, but results are partial and expensive.

4. Essential Tools / Patches

  • Vendor-specific decryptor: None; do not trust any site claiming to have a universal “.eight decryptor” besides the criminals’ Onion.
  • RansomFree / KasperskyAntiRansomware tool: can kill the process mid-encryption but cannot roll already-encrypted files.
  • Microsoft’s “Windows-security-update-2023-09” rollup fixes CVE-2023-36884 abused by recent “.eight” chains.
  • NirSoft’s “ShadowCopyView” – run from unaffected workstation to verify if any shadow copies survived before re-imaging.

5. Other Critical Information

  • Unlike “big-game” families that exfiltrate data, .eight is encryption-only; to date, no Tor site for posting victims’ files has been observed. That does not remove breach-disclosure duties if personal data was impacted.
  • Because it appends a clean, predictable extension, many sysadmins detect the outbreak by e-mail rules alerting on any “.eight” file creation – the simplest early-warning you can build today (PowerShell: Get-ChildItem –Recurse –Filter *.eight -ErrorAction SilentlyContinue | Measure-Object).
  • The malware tries but fails to encrypt on ReFS volumes; moving highly critical data to a ReFS share (Server 2022) gives an extra layer of protection (not a replacement for backups).
  • IOCs rotate quickly; subscribe to your national CERT or a threat-intel feed for hash updates rather than relying on a static list.

Remember

Backups are the only free “decryptor” that always works.
If this is your first encounter with “.eight”, treat it as an opportunity to button up the basics: MFA, least-privilege, offline recovery media, and a rehearsed incident-runbook. Stay safe.