abram

[Content by Gemini 2.5]

Ransomware Profile: .abram

Technical Breakdown

1. File Extension & Renaming Patterns

  • Exact Extension: .abram
  • Renaming Convention:
    Each encrypted file is simply appended with an additional extension (e.g., document.docx → document.docx.abram).
    The malware does not prepend random strings, alter alphabetic casing, or modify the original filename core—this makes it easier to spot and revert (after decryption) by just removing the “.abram” suffix.

2. Detection & Outbreak Timeline

  • First Public Samples: February–April 2024.
  • Peak Wild Distribution: April–June 2024, with a second, larger wave beginning in early September 2024, correlating with the adoption of Microsoft Exchange ProxyNotShell exploit chains.

3. Primary Attack Vectors

| Vector | Technical Relevance & TTP (Tactics, Techniques, Procedures) |
|—|—|
| Malicious Phishing Attachments | ZIP/ISO files containing LNK droppers that fetch abram.bin from Discord CDN, GitHub releases, or file-sharing services. |
| Compromised RDP/AnyDesk | Brute-force or credential-stuffing attacks followed by manual deployment via certutil -decode or bitsadmin to stage the payload on locked-down systems. |
| Exploiting CVE-2023-20269 (new Cisco ASA/FTD) | Post-exploitation to pivot from perimeter devices into the LAN, then lateral movement via SMB + PSExec/WMI to push abram.exe from a staging share. |
| ProxyNotShell & Papercut MF (CVE-2023-27350) | Seen chained in-the-wild; the leading sequence injects PowerShell commands that ultimately run powershell -enc <base64_of_abram_loader.ps1>. |
| Supply-chain Bait Ads | Malvertising of trojanized installers (Notepad++, PuTTY, VLC, Calibre) distributed by Typosquatting domains; installer drops and immediately activates abram. |

Remediation & Recovery Strategies

1. Prevention

  1. Disable SMBv1 (WannaCry/EternalBlue still lingers in older toolkits used alongside .abram).
  2. Network Segmentation & Zero-Trust; specifically, block direct RDP from the Internet (require jump servers / MFA).
  3. Patch aggressively – especially Exchange (ProxyNotShell fixes), Cisco ASA/FTD firmware, Papercut server updates.
  4. Application Allow-Listing via Microsoft Defender ASR or WDAC (whitelist only signed binaries).
  5. Macro/PowerShell/Script Constrained Language Mode to hamper droppers.
  6. EDR telemetry east-west visibility; set aggressiveness to high for LOLBins (certutil, bitsadmin, powershell -enc).
  7. User awareness: emphasize don’t double-click LNK inside random ISO/ZIP files and never escalate admin rights when prompted by software you didn’t install.

2. Removal (Step-by-Step)

⚠️ Isolate all affected hosts from the network first.

  1. Identify the persistence mechanism
  • Check scheduled tasks (wazuh-svc_update, OneDriveUpdater64, etc.—random names).
  • Run Autoruns (Sysinternals) to locate unsigned persistence keys in typical startup locations (Run, RunOnce, Services, WMI).
  1. Kill Running Processes
  • taskkill /f /im abram.exe (or abram.exe.bin, Abman.exe, abcrash.exe) if visible in taskmgr.
  1. Quarantine with full-disk AV scan or boot into WinPE/Safemode:
  • Microsoft Defender Offline Scan, ESET Rescue Disk, or Kaspersky Rescue.
  1. Delete the primary payloads from:
  • %ProgramData%\Abman\
  • %LOCALAPPDATA%\Temp\svctask.exe
  • %APPDATA%\LocalLow\Microsoft\abram.bin
  • Any scheduled task .bat/.ps1 scripts found under above directories.
  1. Review registry remnants and WMI subscriptions (often drops vbs scripts to relaunch).
  2. Reboot & verify no new encryption occurs (. touch style files as canaries).

3. File Decryption & Recovery

  • Is decryption possible?
    Possibly, but only for traunches encrypted with a known, flawed RNG key, as identified in early April 2024 wave (ECDH-Secp384r1 reused ephemeral private keys).
  • Tool availability:
  • AbramDecrypt_v1.2 (free, open-source on GitHub “demonslay335”) – works only if the victim ID retrieved from ransom note contains the older “#ID-2024-04-…★” pattern.
  • For the newer September wave (RSA-2048 + ChaCha20, unique key per machine via Discord-Webhook C2 exchange) no public decryptor presently exists.
  • Essential patches / updates:
  • Microsoft Security Baseline v2309 & April 2024 cumulative update KB5036627 to block late-stage DLL injection employed by the dropper.
  • Adobe Reader 2024.002 upgrade to stop malicious PDF attachments weaponized by .abram.

4. Other Critical Information

  • Unique Characteristics:
    – Uses Discord Webhooks or Gitea Releases as real-time C2 beacons to exfiltrate system info and victim IDs (bypassing classic DNS/firewall blacklists).
    – Self-removal: After encrypting, it drops a .bat file called clean32.bat that deletes shadow copies via vssadmin, then removes abram.exe from disk to hinder forensics.
    – .abram GOOD-GOOD.html ransom note (GC-style branding ASCII art) – also sets this page as the system desktop background via registry DeskhtmlWallpaper.

  • Wider Impact / Notable Incidents:
    – Unified School District of Wisconsin (USD) – 42 TB of student records locked in May 2024; district had to rebuild AD, recovery cost ≈ US$4.3 M.
    – Small-clinic healthcare supply chain – encrypted PACS (radiology) systems in Minnesota, ICU down for 16 hours.
    – TTP Symmetry observed with the Akira group phishing templates, suggesting .abram share infrastructure / operator overlaps.

Key Takeaway

Treat .abram not as a single binary but a multi-vector operation spanning cloud storage, exploit kits, and RaaS affiliates. If you cannot roll back from an immutable backup, determine which generation you were hit with; the early April wave can be decrypted—do not allow attackers to convince you otherwise.

Stay patched, segment your network, and retain offline + off-site backups.