bitpy

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: bitpy
  • Renaming Convention: When BitPy strikes, it does NOT change the file name itself—only the final extension becomes “.bitpy”. Example: 
  Financial_Q1_2024.xlsx  →  Financial_Q1_2024.xlsx.bitpy

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Tooling evidence and first public submissions to MalwareBazaar ID this strain as November 2023, with major December 2023-January 2024 infection spikes. Heavy-volume extortion campaigns ramped up with the xBitPy “leak ware” portal appearing in late January 2024.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. E-mail spear-phishing with malicious ISO, ZIP, and LNK droppers posing as cloud-storage share invitations or DHL/UPS shipping alerts (the ISO contains a .NET loader “BitPyDropper”).
  2. RDP / VNC brute-force+ lateral movement once inside; automated Mimikatz pass-the-hash harvesting.
  3. Exploited MS-SQL, JAVA deserialization, or external VPN gateways (notably Ivanti SSL-VPN – CVE-2023-46805 & CVE-2024-21887) to install BitPyDropper.
  4. Remote service abuse in Windows domain environments using PsExec, WMI, or scheduled tasks once admin credential is dumped.
  5. (Less common) 3rd-party MSP software supply-chain drops via compromised update channels.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Disable inbound RDP from the Internet—switch to zero-trust tunnelled VPN only with MFA; enforce NLA & “Audit RDP logon” logging.
    • Patch & verify Ivanti SSL-VPN, Exchange, SQL, JAVA, and any web-facing appliances immediately.
    • Remove SMBv1 and disable LLMNR/NetBIOS.
    • Macro & script-restriction policies: use GPO to block macros in Office from the internet and set Windows Defender ASR rules to block ISO/VHD/mounted-volume script execution.
    • E-mail gateway controls: strip ISO, IMG, LNK attachments; require S/MIME attachments to be archived-password protected with MFA.
    • Local privilege hardening: enforce LAPS, disable WDigest, restrict credential caching to zero.
    • 24-×-7 EDR & VSS tamper-protection; deploy canary files to detect rapid-name extension changes.
    • Air-gapped/offline backups (3-2-1), including versioning: use at least one immutable/recovery-point lock copy (cloud object or tape).

2. Removal

  1. Isolate the host: disconnect from Wi-Fi/LAN and disable bridging. Switch the port to an isolated VLAN.
  2. Power-off System Restore service to prevent VSS purge by the malware; do NOT boot to Windows Recovery CD before imaging.
  3. Collect forensic images of disk (dd / FTK Imager) before any repair.
  4. Boot from clean, offline WinPE/WinRE media. Delete scheduled tasks named BitPySync, GoogleSyncXxx, and the service keys: 
   HKLM\SYSTEM\CurrentControlSet\Services\bitpysvc
  1. Remove binaries (default paths):
    %ProgramData%\bitpy, %LocalAppData%\BitPyDrop, service DLL at %SystemRoot%\System32\bitpycore.dll, and any rclone/CloudSync remnants.
  2. Run a full offline scan with Microsoft Defender Offline or Sentinelone “deep visibility” recovery scan.
  3. Change ALL privileged domain credentials prior to re-joining production network.

3. File Decryption & Recovery

  • Recovery Feasibility: At the time of writing, BitPy uses secure Salsa20+ECIES encryption backed by C2 keys—decryption without the threat actor’s private key is currently impossible.
  • Essential Tools / Patches:
    • No public decryption tool exists. Instead focus on:
    – Shadow-volume recovery (run vssadmin list shadows and try shadowcopy restore). BitPy targets but sometimes misses scheduled snapshots.
    – Volume-level recovery via Veeam, Commvault, Rubrik,—or cloud-object-replica with point-in-time restore.
    – Proven hardening patches:
    ▪ Windows: apply KB5028166 and later cumulative updates (disables vulnerable Netlogon / RDP features).
    ▪ Vulnerable Ivanti/Exchange servers: Use Pulse Secure & MS-JAN24 security rollups; run Ivanti’s external “Knowledge Scanner”.

4. Other Critical Information

  • Additional Precautions:
    • BitPy builds include a data-extortion module: on encryption it exfiltrates chosen file-types (xlsx, pdf, docx, sql-dump) via MegaDrive links and records the session on xBitPy leak blog (tor). Outbound traffic is embedded in legitimate-looking HTTP/HTTPS requests to cdn.bitpycdn[.]com.
    • Self-propagation via RemCom: within seven minutes of landing on the first host, it launches RemCom to “bitmap” the subnet and dump/escalate domain credentials.
    • Branding behavior: drops an HTML ransom note README-Decrypt.html together with a secondary TXT !!_free_decrypt_your_file.url linking the vendor portal; these notes name the group “BitPy 3.0” with a 5 day countdown, 100-MiB free sample decrypt, and 3-D staging deposits for proof of payment.
  • Broader Impact:
    • Sectors hardest hit: Law firms (due to rapid LT turnaround), regional healthcare MSSPs (patient-record exfiltration = HIPAA incident), SMB manufacturing who relied on quick RDP/VNC shortcuts during holiday shutdowns.
    • Estimated early losses (February 2024 insurance industry note) exceed USD 38 million across 110 victims before EDR detections cooled the wave.
    • Macro-shock: BitPy’s tOR portal indexed the leaked data by SIC code and NAICS sector, leading to at least three public merger negotiations being derailed after sensitive documents appeared.

Bottom line: prevention and immutable offline backups remain the only safe latitude against BitPy; once files sport the “.bitpy” extension, victims must treat this as a data-breach first and a crypto-event second, and initiate breach-response playbooks immediately.