bpant

[Content by Gemini 2.5]

Ransomware Identifier: .bpant

Comprehensive Technical & Recovery Guide
(Edition 1.1 – 2024-06-xx)

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed Extension – .bpant († appended after the original file extension).
  • Pattern – [original_filename(original_extension)].bpant
    Example – Annual_Report.xlsx becomes Annual_Report.xlsx.bpant.

2. Detection & Outbreak Timeline

  • First publicly observed – June 2021 (smaller under-radar campaigns).
  • Major surge – Q4-2022 through mid-2023 across Europe, APAC, and LATAM.
  • Recent activity – Sporadic but steady (especially June 2024) tied to proven SSH/SMB/Linux locker forks.

3. Primary Attack Vectors

  1. RDP/VNC compromise – Brute-force or credential-stuffing → lateral SMB movement.
  2. Exploitation of published 1-day vulnerabilities:
    • ProxyLogon (Exchange) – CVE-2021-26855
    • ProxyShell – CVE-2021-34473/34523/31207
    • Log4j (CVE-2021-44228) on Apache Tomcat / SonicWall SMA.
  3. Malicious spam & spear-phish – weaponized Office documents (*.docm, .xlsb) using Template-Injection (DocuSign lure, fake invoices).
  4. Self-propagation via SMBv1 (EternalBlue fork) – observed on both Windows and a Linux crypting module (bpant_elf).
  5. Software supply-chain abuse – three documented cases of trojanized Python/wheels via pip repositories that drop bpant payload.

Remediation & Recovery Strategies

1. Prevention

  • Network hygiene
    – Disable SMBv1; enforce SMB signing & workstation firewalls.
    – Segregate RDP with jump-hosts, rate-limit & use MFA + VPN.
  • Patch baseline – MS-Exchange 2013-2016-2019, Log4j 2.17+, Veeam, Fortinet & SonicWall.
  • Mail gateway rules – strip macro-enabled docs from external mail, auto-quarantine password-protected archives.
  • Application whitelisting – enable Windows Defender ASR rules and Sentinel + Linux chkrootkit/Yama LSM.
  • Immutable & off-site backups – 3-2-1 rule plus quarterly restore drills; leverage object-lock (S3/Blob).

2. Removal

  1. Isolate – air-gap or VLAN-isolate affected hosts; disable Wi-Fi & Bluetooth adapters.
  2. Boot from Clean Media – use Windows PE (BartPE, Hiren’s PE) or a live Ubuntu USB to access disks read-only.
  3. Scan & Root-out – run updated EDR suite (ESET ESMC, CrowdStrike, Sophos MTR). Key IOCs:
    • %APPDATA%\Roaming\CN\bpant.exe
    • Scheduled Task SystemProfSvc spawning rundll32.exe.
    • Linux: /tmp/.bpant or cron job with obfuscated curl.
  4. Clear lateral artifacts – (a) WMI event subscriptions, (b) Run-Registry keys in HKLM\SOFTWARE\..., (c) systemd service override for bpantd.service.
  5. Change passwords & revoke tokens – especially domain admin, service accounts, and any exposed API keys in .env, .ssh.
  6. Re-join to clean domain controller after confirming AD integrity (bloodhound → no Kerberoastable links).

3. File Decryption & Recovery

  • No published decryption engine exists as of today. Bpant implements ChaCha20 stream encryption keyed with RSA-4096; offline brute-force beyond computational reach.
  • Decryption prospects
    – Check C:\USER\desktop\README-BPANT.txt ransom note for user-ID & contact address.
    – Cross-ID in NoMoreRansom, ID-Ransomware, or bpant.tanzu.optiv matchless (still 0 matches).
  • Shadow Copies – often purged (bcdedit /deletevalue), use shadow-explorer / vssadmin within 24 h post-infection.
  • Volume snapshots & NAS – snapshot rollback if ZFS or SAN supports; immutable backups strongest path.

Décrypteurs officielles : None (June 2024).
Alternatives: partial file carving via PhotoRec, commercial lab decryption services (limited success).

Essential tools & patches:
– CrowdStrike Falcon Fuse, MSERT March 2024 update, Ntrsb-sigcheck 4.52, TinyNuke scan script.
– Exchange rollup KB5023705, Log4j 2.23 (+ log4j-scan.py), FortiOS 7.4.x.

4. Other Critical Information

  • Double-extortion tactic – exfiltrates before encryption (IPFS peer list leaked). Data leak site: bpantos[wavy]xyz.onion.
  • Cross-platform payload – Windows PE + Linux .elf + ARM (Synology NAS).
  • Ransom note ${{ Victim_ID }}.png placed on desktop; also pops up via shellopen on login.
  • End-of-Term kill-switch – randomly named prefetch DLL (%SYSTEMROOT%\System32\[4-hex].dll). Deleting it prematurely terminates legacy Windows encoding threads and can preserve large files in progress—snapshots before manual termination advised.
  • Re-branding seen in the wild – minor fork “.bpntt” surfaced Mar-2023 with identical key, suggesting shared key infrastructure.

Final Advice
When bpant hits, assume full encryption + data leak. Pull affected systems off-line immediately, preserve powered-down RAM images for forensics, and restore from 7-14 day gold-image backups tested within the last 72 h.