alock

[Content by Gemini 2.5]

Alock Ransomware – Comprehensive Response Guide

Technical Breakdown

1. File Extension & Renaming Patterns

  • Exact File Extension: .alock (lower-case and appended without a space).
  • Renaming Convention:
    Original File → original_name.docx.alock
    Each encrypted file keeps its base name and simply receives the additional suffix .alock after the original extension. Unlike some families that insert unique IDs or e-mail addresses, alock’s naming is very clean—making it easy to spot in bulk listings.

2. Detection & Outbreak Timeline

  • First Public Sighting: March 2023 (initial uploads to ID-Ransomware & VirusTotal around 15–20 Mar 2023).
  • Major Surge: April–May 2023 campaigns targeted small-to-mid-size healthcare and law-firm networks, focusing on the U.S., U.K., and Australia. While total volume is lower than Kingpin families (e.g., LockBit), incident rates still trend upward quarterly.

3. Primary Attack Vectors

  • Exploited Vulnerabilities:
    • MS17-010 (EternalBlue) for lateral SMB spreading once an initial foothold is achieved.
    • Log4Shell (CVE-2021-44228) in rare cases against Java-based application servers.
  • Entry Door:
  1. Phishing e-mails carrying password-protected ZIP (.zip) files that launch a GoatLocker dropper (alock’s packager).
  2. RDP brute-force / credential stuffing on exposed 3389/TCP ports followed by manual deployment of the alock console tool (alock.exe).
  • Secondary Propagation: Uses PsExec and WMIC with harvested domain credentials once inside.

Remediation & Recovery Strategies

1. Prevention

  • Patch Immediately:
    • Apply official Windows patches for MS17-010 & SMBv1 hardening. Disable SMBv1 globally via Group Policy.
    • Apply log4j2 v2.17.1 or later to any vulnerable Java stacks.
  • Network Hardening:
    • Close RDP to the Internet; move to VPN-only access and enforce NLA + MFA.
    • Segment VLANs and restrict lateral SMB/NetBIOS via Windows Firewall.
  • E-mail & Endpoint Controls:
    • Disable macro auto-execution in MS Office, and quarantine any password-protected ZIP from external senders.
    • Deploy EDR/NGAV with behavior-based detections (e.g., Windows Defender ASR rule: “Block credential stealing from LSASS”).
  • Backups: Follow 3-2-1 with at least one offline immutable copy (Veeam Hardened Repository, AWS Object Lock, WORM tape, etc.).

2. Removal (Step-by-Step)

  1. Disconnect the affected host(s) from LAN/Wi-Fi.
  2. Boot into Safe Mode with Networking to stop obfuscated services.
  3. Kill the alock process(es):
    • alock.exe, often residing in %TEMP% or C:\Windows\Temp.
    • Scheduled Tasks named AlLockUpdate or AlSvc. Remove them from Task Scheduler or via schtasks /delete /tn AlLockUpdate /f.
  4. Delete residual binaries:
    • %APPDATA%\alock-ransomware\ directory
    • Survivorship Key logging module: DLLSvc32.log
  5. Run a reputable AV/EDR scan (Malwarebytes, ESET, MSERT, etc.) to purge any remaining modules.
  6. Check registry run-keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) for persistence entries such as AlLockRunner.

3. File Decryption & Recovery

  • Current Decryptor Status: No public decryptor exists for alock (as of 2024-06-17). The AES-256 + RSA-2048 encryption employs per-file session keys encrypted to an attacker-supplied public key; RSA private key is not exposed.
  • Recovery Options:
    • Down-payment-free test decryption is promised on some ransom notes, but history shows slim success; do not pay unless no other exit and legal/compliance review approves.
    • Shadow Copies: Rarely purged—check via vssadmin list shadows and use ShadowExplorer if intact.
    • Immaculate backups: Restore from offline backup to the most recent clean recovery point.
    • Niche forensic avenues: If an endpoint crashed mid-encryption, remnant un-encrypted copies (*.tmp, *.~) may exist in original paths or Recycle Bin.

4. Other Critical Information

  • Unique Characteristics:
    • Ships with a Go-based dropper (compressed UPX ELF/EXE) that auto-selects either 32- or 64-bit payload during deployment.
    • Ransom Note: README_RECOVER_ALOCK.txt is always dropped in every folder with a fixed Bitcoin address (bc1…f3e4) and a semaphore file %USERPROFILE%\alock.failed to prevent re-encryption on reboot.
  • Detection Rules for SOC Teams:
    • YARA:

    rule Alock_Signature_v1 {
    strings:
    $a = "ALOCK_ENCRYPT_XORKEY_1337" wide
    $b = "AlLockIsDataNachEncrypt" ascii
    condition:
    uint16(0) == 0x5A4D and (any of them)
    }
  • Impact:
    • Mainly SMB-reliant SMEs; average ransom ask ≈ 0.75–2.75 BTC.
    • Creates service disruption > data exfiltration—alock does not steal data, making double-extortion rare compared to Maze/Conti pattern.
    • The .alock extension is visually similar to ALPHV/BlackCat (.alphv / .black), causing false-triaging; note filename cleaner (no “RESTORE-XXX.txt”).

Stay vigilant—keep security controls layered, backups untouchable, and never trust a single vector explanation.