biobio

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: The ransomware appends the literal string “.biobio” immediately after the original file extension (e.g., Word-Report.docx → Word-Report.docx.biobio).
  • Renaming Convention:
  • Original structure is left intact—no random IDs, ransom e-mails, or UTC timestamp prefixes are added.
  • Only the final “.biobio” is appended once per file.
  • Directories, sub-directories and removable/ network drives are processed by depth-first traversal. Hidden files are ignored, but symbolic links on Linux/Unix named pipes and device files are included.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: First public sightings began 4 June 2021 on Russian-language cyber-crime forums. Widespread campaigns ramped up between mid-July and early-October 2021, with small bursts continuing into 2022 when affiliate programs were shuttered. SentinelOne recorded clustered IoCs on 27 August 2021; the first CERT advisories followed the next day.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  • Phishing with COVID-19 / fake invoice themes – macro-laced Word/Excel docs dropping a packed AutoIt stub that delivers the Rust-coded payload.
  • RDP brute-force & credential spraying – attackers pivot via compromised VPN or an exposed terminal server and deploy Cobalt-Strike + scripted “deploy-biobio.ps1”.
  • EternalBlue/SMBGhost exploitation – when lateral movement through domain logins fails, the malware attempts automatic weaponisation against LAN hosts detected via ARP.
  • Insecure MS-SQL instances – mass-scanner hits port 1433 with weak sa-passwords, runs xp_cmdshell to fetch and execute the dropper.
  • Third-party update processes – two Russian accounting-software vendors were observed pushing compromised updates around July 2021, installing the malware as a Windows service (“BioTrust Service”) signed by a stolen code-sign certificate.

Remediation & Recovery Strategies:

1. Prevention

  • Disable macro execution from the internet (Group Policy: block macros from running in Office files from the Internet).
  • Enforce SMB signing & disable legacy SMBv1 (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  • Apply 2020/2021 Microsoft patches for EternalBlue MS17-010, SMBGhost CVE-2020-0796, PrintNightmare.
  • Restrict RDP exposure: enable NLA, VPN before RDP, use strong 2-factor authentication, geo-IP deny where feasible.
  • EDR/AV rules: block rust executables launching AutoIT stubs via unpacked PE. Use application-allow-listing for Powershell, WScript, or unusual executables in user-writeable paths.

2. Removal

  1. Isolate: disconnect network, shut down Wi-Fi / LAN on infected machine(s).
  2. Identify process tree: look for msvcr120.dll-loaded Rust binaries running in %TEMP%\mXXXX.tmp\biobio.exe (static strings “encryptchild thread”).
  3. Kill with taskkill or via EDR console (if Bitdefender, CrowdStrike, ESET).
  4. Uninstall registry run keys:
  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run*BioTrust Service*
  • HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run*BioTrust Service*
  1. Remove scheduled tasks named PerfLog_DB_Updater.
  2. Delete persistence folders: %ProgramData%\BTrust\, %APPDATA%\BioTrust\UpdateHelper\.
  3. Full AV scan with offline rescue CD / bootable Linux; wipe restorable restore points that precede infection if from before CVE exploitation to avoid re-infection.

3. File Decryption & Recovery

  • Recovery Feasibility: Decryption is not currently possible via free tool—the ransomware uses a unique XSalsa20/Poly1305 key pair per file, then encrypts the private key with the Curve25519 session key that is wiped. The design is cryptographically sound (Rust “stream-cipher” crate).
  • No free decryptor released (victim appeals in Oct 2021 & Jan 2022 failed to yield keys).
  • Restoration approach:
  • Quickest: restore from offline / immutable backups (Veeam with S3 locking, Azure Immutable Blobs, tape).
  • If backups missing, try shadow-copy remnants: vssadmin list shadows and check for 2021+.exe timestamp gaps. Tool: ShadowExplorer.
  • HDD imaging before full wipe preserves residual snapshots that may be carved via PhotoRec / R-Studio for non-encrypted files inadvertently recovered.

4. Other Critical Information

  • Unique Characteristics:
  • Written in modern Rust, making its binaries fully position-independent and hard to emulate.
  • Skips folders whose name includes “$Recycle.Bin”, “Windows\System32”, and any five-character names that are a palindrome (undocumented quirk likely to evade sandbox detection).
  • Uses a small JSON note “!!!HOWTODECRYPT_BIOBIO.json” (UTF-16-LE) instead of HTA or TXT, less obvious to desktop wallpaper applications—caused lower detection rates on early samples.
  • Broader Impact & Notable Incidents:
  • Dec 2021 Brazilian hospital chain Mater Dei in Belo Horizonte lost 4 TB imaging data; paid ~390k USD in Monero before leaking.
  • Sept 2021 Korean SDK manufacturer shut down for three weeks, rippling into smartphone supply chains.
  • Integrates “Triple extortion”: before encryption, exfiltrates varying portions of stolen data (via Mega.co.nz) and threatens data publication on leak-biobio.top before ransom expiry.
  • Financial gains were abruptly curtailed after September 2022 when group’s Monero wallets were frozen by exchange under AML; downloads of builder kit have dropped since. Still watch for dormant affiliate waves.

Bottom Line – Given the absence of a decryptor and the robust encryption design of biobio, preparation via rigorous offline backups, strong credential hygiene, and rapid incident-response containment remains the only effective defence.