cerber

Technical Breakdown:

1. File Extension & Renaming Patterns

• Confirmation of File Extension: Cerber’s current and historic waves append .cerber, .cerber2, .cerber3, and so on (the number increments with each major variant). Most victims today encounter .cerber5, .cerber6, or the variant-suffix .cbf47 / .a8d2f.
• Renaming Convention:
  Original filename: Quarterly-Report.xlsx
  Encrypted: Quarterly-Report.xlsx.cerber6
  Additionally, the malware stores each victim’s unique “personal ID” (10 hex characters) at the beginning of every ransom note and inside the registry (HKCU\SOFTWARE\Cerber\<id>) to track payments.

2. Detection & Outbreak Timeline

• First appearance: March 2016 (Cerber v1)
• Major surge: May–September 2016 (versions 2–3) utilizing the Angler Exploit Kit
• Evolution timeline:
  • Dec 2016 – v4 introduced offline encryption keys
  • Feb–Apr 2017 – v5/v6 shifted heavily to RDP brute-force + botnet spam
  • Oct 2017 – operations scaled down; source code reportedly for sale on underground markets, but individual affiliates still see sporadic use into 2024.

3. Primary Attack Vectors

• Classic approaches:
  • Phishing e-mails: Office macros, .js, .wsf, .hta attachments disguised as invoices or CVs.
  • Exploit Kits: Angler, Neutrino, and Magnitude served via compromised web advertising (malvertising).
• Active intrusion:
  • RDP brute-force: Scans port 3389 for weak credentials; installs Cerber payload via batch scripts or PSExec.
  • EternalBlue (MS17-010) & DoublePulsar: No known Cerber build uses these directly; focus is on credential compromises.
  • Software flaws: Outdated MS Office CVE-2017-11882 hiding exploits inside documents that launch Cerber’s loader.