erif

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Exact Extension Used: Files are re-written with the single extension “.erif”.
  • Original document.docx → document.docx.erif
  • Original spreadsheet.xls → spreadsheet.xls.erif
  • Naming Convention: No e-mail address or ransom ID is inserted into the file name; only the literal string “.erif” is appended.

2. Detection & Outbreak Timeline

  • First public appearances on ID-Ransomware, Twitter and support forums: late-January 2023 (payload compiled 21 Jan).
  • Rapid uptick through February-mid March 2023; still circulating as of 2024, delivered alongside STOP/DJVU’s weekly site-compromise waves.

3. Primary Attack Vectors

All vectors mirror the STOP/DJVU distribution machine—erif is simply the latest campaign ID:

  • Malvertising / poisoned search results: “software crack/keygen”, “free Photoshop”, game cheats.
  • Malspam attachments: ZIP→JS, ISO→LNK, or macro-enabled Office files that fetch the .EXE.
  • Bundle with RedLine / Vidar info-stealers: installed seconds before erif.exe runs.
  • Abuse of Windows’ built-in tools:
  • nslookup for DGA lookup;
  • wmic shadowcopy delete;
  • bcdedit /set {default} safeboot network followed by vssadmin delete shadows /all.
  • No EternalBlue or SMBv1 exploits observed—all infections start with user-executed code or drive-by download.

Remediation & Recovery Strategies

1. Prevention

  • Block execution of files from \AppData\Local\Temp*, %Public%, and any path whose name = “crack”, “patch”, “keygen”, “loader”.
  • Install current browser / PDF / Office patches; disable Office macros centrally.
  • Use Defender ASR rules: “Block executable files from running from downloads” and “Block Office apps creating executable content”.
  • Keep at least one offline/cloud backup with versioning/object-lock (S3 Object-Lock, Azure Immutable Blob, Veeam Hardened Repo, USB that is physically unplugged).
  • Restrict RDP and other perimeter exposures—erif is not reliant on them, but secondary backdoors (Cobalt, RedLine) that precede it do.

2. Removal (Step-by-Step)

  1. Isolate host immediately: disconnect NIC / disable Wi-Fi.
  2. Collect logs:
  • C:\SystemID\PersonalID.txt – this file contains your victim ID and the public key; back it up.
  • %TEMP%[random]\updatewin.exe – usually the erif dropper.
  1. Boot into Safe-Mode-with-Networking (or WinRE if Safe-Mode is disabled).
  2. Run current AV/EDR:
  • Microsoft Defender, Malwarebytes, Sophos, Bitdefender, ESET, Kaspersky all detect the current build as “Ransom:Win32/STOP”.
  • Allow the scan to remove payloads and scheduled tasks (“Time Trigger Task”, “Windows Update Loader”, “ServiceName Task”).
  1. Delete any “autorun” entries added under
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run
  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run
  • Values: “ServiceName” / “SysHelper” / random GUID.
  1. Reboot normally; if the system is stable, move to recovery phase.
  2. Before restoring data, wipe and reload Windows if:
  • RedLine/Vidar or any RAT was observed; otherwise, full AV/EDR pass is sufficient.

3. File Decryption & Recovery

  • Online-ID infections (>90% of cases since Q1-2023): Each victim receives a randomly generated key pair stored on the criminals’ server.
  • Decryption NOT possible at this time—no flaws in the Salsa20 + RSA-2040 implementation have been found.
  • The free STOP-Decrypter (Michael Gillespie/Emsisoft) supports erif but can only recover files when:
    • PersonalID.txt ends in “t1” (offline key) AND the corresponding private key has been donated by a victim who paid;
    • For “t1” machines the decryptor shows “key is available”. Otherwise it returns “no key for this variant”.
  • Recovery Fallbacks:
  • Volume-Shadow copies (check vssadmin list shadows/shadowexplorer).
  • Windows “File History” backups if configured.
  • Cloud recycle bins: OneDrive “Files Restore (30 d)”, Google Drive version history, Dropbox rewind, etc.
  • Photo / RAW recovery carving tools (PhotoRec, Recuva, R-Studio) can resurrect unencrypted copies from formatted SD/USB if no TRIM has occurred on HDD.
  • Snapshots on NAS (Synology BTRFS, QNAP ZFS) usually survive the attack; replicate new snapshots before restoring.

4. Essential Tools / Patches

  • Latest decryptor: EmsisoftDecrypterForSTOPDjvu.exe v1.0.0.7+ (get straight from Emsisoft.com or BleepingComputer; ignore third-party “.erif decryption” payware scams).
  • Security update: Windows patch level must be 2022-09 or later so that Defender engine≥1.387 contains STOP/erif sigs.
  • OSSEC/Wazuh rule #25501 added in 2023 detects scheduled-task names used by erif; import XML into SIEM.
  • LocalGroupPolicy to deny the exact file hashes—Microsoft publishes IoCs daily under “Ransom:Win32/STOP” family.

5. Other Critical Information & Wider Impact

  • Double extortion? NO. Erif/STOP does NOT exfiltrate data, but the RedLine stealer deployed with it very often does—assume workstation credentials and browser cookies are compromised and rotate passwords from a clean device.
  • Network shares hit via mapped drives only—no worm functionality. However, the malware deletes 12 zeroes at the end of each file and rewrites with random bytes, interrupting dedupe/replication targets and corrupting Git, Outlook PST and SQL MDF files.
  • There have been fake “decryptors” built to harvest additional BTC from despairing victims. A real erif decryptor is and always will be free; any vendor charging money for it is a scam.
  • Overall footprint: >600 submissions per month on ID-Ransomware alone, ranking erif among the top-three STOP strains in 2023 alongside “guza” and “kizu”. Patch, backup and deny “cracks” and the risk effectively drops to zero.

Use the above playbook to contain existing infections, rebuild safely, and—most importantly—prevent the next wave. Backup discipline remains the single decisive factor; everything else is secondary.