cerbersyslocked0009881

[Content by Gemini 2.5]

Cerber (variant pattern string: cerbersyslocked0009881) Resource

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: encrypted files are given the static extension .cerbersyslocked0009881 (15-digit suffix that never changes across victims).
  • Renaming Convention:
    OriginalName.Ext.cerbersyslocked0009881
    Example:
  • Quarterly_Report.xlsx → Quarterly_Report.xlsx.cerbersyslocked0009881
    Folder names themselves are NOT altered; only their contained data.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
  • Early-April 2020 – new wave of Cerber payloads started using the hard-coded token cerbersyslocked0009881 after operators spun up fresh C2 domains (re-registered 29-March-2020, captured by security researchers 02-Apr-2020).
  • The pattern “cerbersyslocked” was already reported by victim forums in October 2019, but the exact suffix 0009881 only appeared in April 2020 campaigns.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. Phishing Emails – ZIP/RAR files with obfuscated JavaScript downloaders (MS Word Docm macros observed 08-Apr-2020).
  2. RDP Brute-Force – scans for TCP/3389 open to internet; default or weak passwords trigger the dropper (rdp-service.exe).
  3. EternalBlue (MS17-010) – SMBv1 exploit still used against unpatched Win7/Server 2008 systems to propagate laterally inside a network.
  4. Compromised Managed Service Providers (MSPs) – Cerber affiliates gain access via legitimate remote tools (ScreenConnect, Atera) and push the payload to hundreds of endpoints at once.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures
  • Patch immediately for MS17-010, CVE-2019-0708 (BlueKeep), CVE-2020-0688 (Exchange).
  • Disable SMBv1 on every Windows system.
  • Harden external RDP: restrict to VPN, enable NLA, rate-limit + deny-after-N-attempts on firewalls.
  • Require MFA for all remote-access tooling.
  • Email filtering: sandbox macro-enabled Office docs and block executable JS/WScript inside ZIP files.
  • Backups 3–2–1 rule (3 copies, 2 media, 1 offline); verify restore tests monthly.

2. Removal — Infection Cleanup

  1. Power-down ransom-struck systems you cannot isolate to prevent further encryption.
  2. From a clean computer, create an offline bootable AV scanner (e.g., Microsoft Defender Offline, Kaspersky Rescue Disk).
  3. Boot suspected machines into the scanner. Remove every cerber task scheduled (common name: WindowsDefenderWinJob).
  4. Purge payloads under:
  • C:\Users\Public\Libraries\
  • %APPDATA%\Roaming\Spoolsv\
  • <systemdrive>\Intel\ (fake Intel folder).
  1. Clean registry autostarts under HKCU\Software\Microsoft\Windows\CurrentVersion\Run and RunOnce.
  2. Run a second scanners pass (Malwarebytes, ESET, Sophos) until zero detections.
  3. Document hosts and revoke stale credentials before bringing machines back online.

3. File Decryption & Recovery

  • Recovery Feasibility:
  • NO public decryptor exists for this suffix (cerbersyslocked0009881). Files use AES-256 with unique keys RSA-encrypted per victim—private keys stored on C2 servers only (active since at least 08-Apr-2020).
  • Old Cerber releases (2016) had leaked master keys – do NOT attempt those; the extension strings and code-signatures are different.
  • Essential Tools/Patches:
  • Ransomware ID site (id-ransomware.malwarehunterteam.com) – confirm whether observed samples match known decryptable strains.
  • Windows Recovery Tool -> Previous Versions (shadow copies): Cerber now deletes them automatically via vssadmin delete shadows /all /quiet—so unless backups are external, this is rarely viable.
  • Volume-level backups (image, VEEAM, Acronis, external USB/NAS) are the only reliable recovery path currently.

4. Other Critical Information

  • Unique Characteristics:
  • Network-aware propagation: internally drops scanner.exe + payloads named after system32 DLLs to blend in.
  • Voice message ransom note (text-to-speech WAV dropped in Public\Music). Cerber is one of few ransomware families to taunt users with an audio file.
  • Appends the identical suffix cerbersyslocked0009881 regardless of strain generation or affiliate code (hard-coded string) – useful for IOC hunting.
  • Broader Impact:
  • Healthcare and municipality sectors in the United States were heavily hit by this wave; various US states report >150 hospital endpoints encrypted in Q2-2020.
  • Because old Cerber keys do not work and decryption vouchers expired, victims report double extortion: data stolen and later leaked on hacker forums if ransom not paid.
  • Interpol and NCCIC advise treating Cerber resurgence as high-priority phishing theme campaigns, owing to adversary reuse of COVID-19 lures.

Use the script below to hunt for the persistence artefacts:

# PowerShell IOC Hunt
Get-CimInstance Win32_NetworkConnection | Where {$_.RemoteName -match "cerber|loki|locker"} | Format-Table
Get-ScheduledTask | Where {$_.Actions -like "*cerber*"} | Select TaskName,State,Actions

Quick reference poster (shareable): 

Backup. Patch. Harden RDP. Block macros. Never pay—these Cerber keys are NOT leaked.

Stay secure, stay patched.