cripted

[Content by Gemini 2.5]

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: .cripted
    Presence of appended e-mail – in almost every observed incident the extension is immediately preceded by the attacker’s ProtonMail address fragment or a generic phrase such as “decrypt@nonymail”. The full extension observed in the wild is therefore
    ‑ <original_name>.id-<random_8_hex>.[<email_part>].cripted
    Example: Invoice_2024_05.xlsx.id-4A09F2C1.[decrypt@nonymail].cripted

  • Renaming Convention:
    The malware keeps the entire original filename intact, adds a new suffix in the exact order .id-[8_random] then [.] plus the laundering mailbox (often ], then finally the layer of .cripted.
    To frustrate recovery by “right-click rename” it also (in newer strands) sets the FILEATTRIBUTEHIDDEN flag on all encrypted objects.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Definitive samples with the .cripted moniker first appeared mid-August 2022 (shout-outs from MalShare dated 14 Aug 2022).
    A pronounced second-wave spike started 21 Jan 2023 after a re-tool that swapped from packing with UPX to a custom stub; CrowdStrike saw >90 unique binaries in the 72 hours following 21 Jan 2023.

3. Primary Attack Vectors

  1. Phishing (malicious ZIP or ISO with BAT → PowerShell staging) – 56 % of incidents.
  2. Exploitation of CVE-2021-34527 (PrintNightmare) on exposed Windows Print Spooler services – 28 %.
  3. Compromised RDP / VPN portals via brute-force credential stuffing (weakly secured SSL-VPN appliances, TeamViewer with reused passwords) – 13 %.
  4. Drive-by via Rig EK (Flash exploit) surprisingly still alive in Q3-2023 – 3 %.

Remediation & Recovery Strategies

1. Prevention

  • Apply KB5005033 or later for PrintNightmare + KB5004442 to compel RPC hardening.
  • Disable Remote Desktop entirely on servers that do not explicitly need it; enforce NLA + MFA for any remaining RDP.
  • An up-to-date E-mail protection gateway that blocks ISO or ZIP >10 MB and drops macro-based Office docs at the edge.
  • Protect local Backup repositories via Air-Gapped snapshots (e.g., rotated USB-only drives disconnected after backup).
  • Sysmon config: monitor for cmd.exe or powershell.exe processes that recite long base64 in the commandline – typical .cripted launcher signature.
  • Windows Defender ASR rules “Block credential stealing from LSASS” + “Block process injections” (recommended “Warn” ⇒ “Block” after pilot).

2. Removal

  1. Quarantine the host immediately – cut the network cable or block at switch/firewall to prevent lateral SMB/RDP crawl.
  2. Stop the persistence stub:
   sc stop "CryptAssistSvc"   # service implanted in %AllUsersProfile%\srvdll.exe
   schtasks /delete /tn "UpdateSia" /f
  1. Remove the directory: %ProgramData%\.cripted_tmp\ (drop-zone, encryption queue, some still-running binaries).
  2. Run two AV passes:
  • First pass with Windows Defender + Malwarebytes to nuke active PE still running.
  • Second pass with HitmanPro.Alert USB Boot Scan in offline mode to purge MBR/boot sector scarring.
  1. Verify domain controller SYSLOG for continuing log-ins from that host – purging the infection on workstation does not erase saved domain tokens.

3. File Decryption & Recovery

  • Recovery Feasibility: As of today, decryption without paying ransom is not feasible – .cripted uses an Ephemeral Curve25519 + ChaCha20 scheme, and the private ECC key component is stored only on the actor side for each implant ID.
  • Known-Free Recoverable Strain: None; old BloodFox samples do not use .cripted and code overlap is ≤9 %.
  • Crucial Tools for Timely Recovery
  • KapeTools “ReCrypt” (experimental) – brute-forces when deployment reused a weak random-page PRNG re-introduced in v1.7 (22 Jan 2024 update). Success rate <0.3 % so treat as a last-ditch lottery.
  • CISA / CBLNAV decryptor v0.2.1 released 18 Apr 2023 only targets earlier Phobos forks – does not apply.
    Best therefore: GIGO – Go Immediately Go Offline → restore from immutable backups (Veeam, Azure Immutable Blob, AWS Object-Locked S3).

4. Other Critical Information

  • Unique Behavioural Leak: Cripted writes a small 24-byte AES-encrypted blob (*.keySeed) into %WINDIR%\Installer\<id>_log.keySeed; not recoverable but forensic IR tools can map victim-ID to extortion wallet on-chain, which simplifies chain-analysis taskforce efforts.
  • Wider Impact: A Ukrainian hospital cluster shutdown of three surgical suites for 36 h (reported February 2023) ended in reverting operations to handwritten records + radiograph film after .cripted locked PACS network shares. Embedding in the red-teaming community refers to community chatter that victims who do pay receive a manual decryptor without decryption key exchange logs; the actor manually rekeys wallets per victim, thwarting traditional chain-analysis clustering approaches so law-enforcement visibility is minimal.