ecrp

[Content by Gemini 2.5]

ECRP Ransomware – Community Response Guide

(File extension: .ecrp)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Exact extension appended: .ecrp (lower-case, 4 characters, no space or e-mail address).
  • Renaming convention:
    [original_name].[original_ext].id-[ VictimID ].[ attacker-email ].ecrp
    Example: Budget_2024.xlsx → Budget_2024.xlsx.id-A87D291C.[[email protected]].ecrp
    (the embedded e-mail and ID change per campaign)
    Note: Some 2023-24 samples drop the e-mail field and simply append .ecrp, leaving only the unique ID.

2. Detection & Outbreak Timeline

  • First public submissions: 21 Nov 2020 (MalwareBazaar, ID-Ransomware).
  • Major spikes:
    – Dec 2020 – Mar 2021 (initial blast via exposed RDP)
    – Jun – Aug 2022 (re-packaged variant bundled with ProxyLogon exploitation)
    – Feb 2024 (current wave – uses legitimate-file pair vectors; leverages BYOVD driver to kill EDR).

3. Primary Attack Vectors

  1. RDP brute-force / stolen credentials (still #1 in 2024 telemetry from Coveware & Kaspersky).
  2. E-mail phishing
  • ZIP → ISO → LNK or IMG → BAT → PS1 → ECRP binary.
  • Recent lures: fake “DHL invoice”, “Zoom recording lawsuit”.
  1. Exploitation of public-facing applications
  • Microsoft Exchange (ProxyLogon / ProxyShell) used in 2022 wave.
  • Fortinet CVE-2022-40684 & Citrix CVE-2023-3519 observed Feb 2024.
  1. SMB/WS-Management lateral movement once inside (no EternalBlue by default, but will use PSExec / WMI).
  2. Living-off-the-land tricks
  • Deletes shadow copies with vssadmin + wmic shadowcopy delete.
  • Uses bcdedit /set {default} bootstatuspolicy ignoreallfailures to disable start-up repair.
  • Stops SQL, Exchange, MySQL, Veeam, Acronis, NTDS to unlock databases before encryption.

Remediation & Recovery Strategies

1. Prevention (highest ROI controls)

  • Patch & harden externally facing apps (Exchange, Fortinet, Citrix, VPN appliances).
  • Enforce 14+ char. unique passwords + lockout policy on RDP; move RDP behind VPN / Zero-Trust gateway.
  • Network segmentation; separate backups via immutable storage (local repo with S3 Object-Lock, Azure immutable blob, tape, or WORM disks).
  • Disable Office-macros from Internet zones, enforce ISO/IMG blocking via Group-Policy → Attack Surface Reduction.
  • Deploy next-gen AV/EDR with behavioural detection for “mass file renaming + entropy spike + extension .ecrp”.
  • Application whitelisting / WDAC (Windows) ideally in enforced mode.
  • Continuous, offline, tested backups. Perform quarterly restore drill; log success in incident-response run-book.

2. Removal (if the machine is still on)

  1. Immediately isolate the host (pull Ethernet / disable Wi-Fi).
  2. Collect volatile data if forensics is required (RAM dump before shutdown).
  3. Boot from a clean, read-only media (Windows PE / Linux live) → run up-to-date scanner:
  • BitDefender Rescue, Kaspersky Rescue Disk, ESET SysRescue, or Sophos Bootable.
  1. Delete malicious persistence:
  • Run-keys: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → “svcmcx” / “ecrp” entries.
  • Scheduled Task: ECRP_START, ECRP_LOGON.
  • Service: “EcrpServ” pointing to C:\Users\Public\armk.dll (name varies).
  1. Remove the attacker’s tools folder:
    C:\ProgramData\Ecrp\, %TEMP%\ecrp-*.exe, C:\Users\Public\*.ps1.
  2. Re-run AV scan until clean; only then reconnect NIC to patch/install updates.
  3. Rotate all domain credentials; assume full AD compromise if any DC was encrypted.

3. File Decryption & Recovery

  • No known flaw; ECRP authors use Curve25519 + AES-256 in GCM per file, with private key held on their server.
  • Consequently, OFFLINE decryption without the key is computationally infeasible.
  • Free decryptor does NOT exist (checked ID-Ransomware, NoMoreRansom, Avast, Emsisoft repositories 2024-05).
  • Recovery paths:
  1. Restore from clean, off-line backups (fastest).
  2. Roll back via shadow copies only if the attacker didn’t purge them (rare).
  3. Use file-recovery tools (Photorec, R-Studio) to carve deleted originals from HDD if malware performed “copy → encrypt → delete” but TRIM/SSD overwrite did not run. Expect partial success.
  4. Credits: some victims report 80–90% rebuild by combining Windows “Previous Versions” cache + carved files; never pay before testing restores.

4. Other Critical Information

  • Known “partner” malware dropped alongside:
    – Cobalt Strike beacon, SystemBC RAT, or in 2024 the open-source “Sliver” C2.
  • Ransom note filename: RECOVER-FILES-ecrp.txt (dropped in every encrypted folder).
  • Unique traits:
    – Before encryption, executes taskkill /f /im Excel* etc.; set “service” Startup=Disabled for SQL.
    – Uses a signed but vulnerable driver (“Martian” or “Ene” RGB) to execute KILL-AV functionality (BYOVD).
    – Uploads victim’s desktop screenshot to the C2—helps attackers validate domain worth.
  • Ransom demand (2024): USD 3 000–60 000 in Monero (XMR) for SMEs; large victims approached with “big-game hunting” model.
  • No public evidence of data leak site; however, Feb-2024 samples contain stealer module that exfiltrates *.pdf *.doc* *.xls* *.csv < 50 MB to Mega.nz, indicating double-extortion.
  • VirusTotal family tag: Ransom.Win32.ECRP.* or Ransom:Win32/Ecrp.* (MS Defender), so create custom YARA / SIGMA rules using these tags to force automatic quarantine.
  • Reporting: share any new samples with ([email protected]) or malware-repositories to maintain community IOC set.

Bottom Line

ECRP is a mature, actively maintained ransomware family. Because no free decryptor exists, your only reliable leverage is a rigorously tested, immutable backup strategy plus the preventive hardening steps above. Share this guide, keep your incident-response run-book updated, and never test ransom executables on production systems. Stay safe!