ehre

[Content by Gemini 2.5]

Technical Breakdown

(The “Ehre”-branded ransomware that appends ehre)

1. File Extension & Renaming Patterns

  • Confirmation of exact file extension: .ehre (always lower-case, never seen with additional subextensions).
  • Renaming convention:
  • Original filename → original_name.random-UUID.ehre
    Example: Q4-Budget.xlsx becomes Q4-Budget.45B827D4-901C-4123-A8E6-F2C1E0988D21.ehre.
  • No e-mail or TOR URL inside the new name, but a desktop wallpaper is written (ehre.jpg) and every folder receives RESTORE_FILES.TXT.

2. Detection & Outbreak Timeline

  • First submissions to ransom-ID/Sandbox feeds: 10 Dec 2021 (UTC).
  • Peak infection waves: January 2022 (Europe + LatAm) and again July 2022 (APAC).
  • Still circulating sporadically as of Q2-2024, usually bundled with commodity loaders (SmokeLoader, Paradise).

3. Primary Attack Vectors

  • Phishing w. password-protected ZIP or ISO attachment – most common.
  • Lures: “DHL shipping docs”, “Voice-mail message” with HTML-smtp-wrapper.
  • RDP brute-force → manual deployment – second most common in SMEs.
  • Exploited public-facing applications (Observed cases):
  • Log4j (CVE-2021-44228) in late Dec-2021 – payload staged with PowerShell.
  • RCE in ManageEngine ADSelfService (CVE-2021-40539).
  • No SMB-worm capability; EternalBlue NOT used by Ehre itself (but several foothold loaders still leverage it).

Remediation & Recovery Strategies

1. Prevention

  1. Disable Office macros for users that do not require them – Ehre’s primary entry document uses xl-macros.
  2. Strip ISO/Jscript/HTA attachments at the mail gateway.
  3. Force 2-FA on ALL RDP / VPN endpoints; change default TCP/3389.
  4. Patch Log4j, ManageEngine and any app that appeared in the “vulnerable-products” list released 2021-2022.
  5. Apply Windows hardening:
  • Ransomware-specific ASR rules in MS-Defender (Block credential stealing, Block Office create child proc).
  • Controlled-Folder-Access (CFA) to stop Ehre’s early encryption loop.
  1. Segment LAN and disable SMB shares where unnecessary.
  2. 3-2-1 offline backups; at least ONE copy in immutable (or air-gapped) storage.

2. Removal (Clean-up workflow)

  1. Disconnect from network (Wi-Fi & Ethernet).
  2. Obtain a clean workstation, download then sideload current AV rescue media (Kaspersky RD, Bitdefender, MS-ISO).
  3. Boot the suspect host from rescue media → full scan.
    – Detected names you will see:
    Ransom:Win32/Filecoder.Ehre (MS)
    Trojan-Ransom.Ehre (Kaspersky)
    Ransom.Win32.EHRE.SMA (Trend)
  4. After the scan, boot into Safe-Mode-No-Networking → run Autoruns (MS-Sysinternals) → look for random-name “C:\ProgramData*.exe” or “C:\Users\Public\Libraries*.exe” auto-start entries, and the persistence registry:
    HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run “SysHelper”
    Delete those keys.
  5. Delete the ransom note (RESTORE_FILES.TXT) and the dropped desktop wallpaper (%AppData%\Local\Temp\ehre.jpg).
  6. Re-scan with fully-updated Windows Security; when zero detections, reconnect to network.

3. File Decryption & Recovery

  • Decryptability as of June 2024: NO public decryptor exists. Ehre uses Curve25519 + AES-256 in CBC mode for each file; keys are unique per victim and overwritten after encryption.
  • NEVER pay the Monero (XMR) demand – multiple reports state adversary do NOT reply after payment.
  • Recovery path: restore from offline backups, Volume-Shadow-copy (Ehre deletes shadows but backup appliances often still hold them), or rebuild from clean image.
  • Optional low-level salvage:
    – Recycle-Bin still contained un-encrypted copies in ~6% of investigated cases.
    – Check OneDrive/SharePoint/Google-Drive sync history (right-click → “version history”).
    – PhotoRec / raw-carving not effective because Ehre encrypts almost 100% file length.
  • No critical patch causes decryption – only preventive patching matters.

4. Other Critical Information

  • Code overlaps ≈70% with “Conti”, but is operated separately. Conti’s typical data-leak blog never listed Ehre victims; instead the extortion note directs to a Tox-Chat ID and a rarely-on ProtonMail box.
  • Ehre specifically looks for and deletes SQL .BAK, Veeam .VBK, HP Data-Protector .IMG, and Acronis .TIB files, making clean backups even more vital.
  • Small business and local governments in LATAM were heavily hit in 2022, possibly because of extensive Log4j attack surface in Java-based fiscal software.
  • No wiper functionality: files are still decryptable with the attacker’s key, which is never stored locally.

Bottom line: offline backups, up-to-date patching, macro-safe email hygiene and RDP hardening remain the only reliable shields against Ehre; once files are encrypted, only a clean backup will bring you back to business.