bin2

[Content by Gemini 2.5]

──────────────────────────────────────────
Bin2 Ransomware Threat Resource
──────────────────────────────────────────

Technical Breakdown

1. File Extension & Renaming Patterns

• Confirmation of File Extension: After encryption every affected file receives the literal suffix .bin2.
• Example: Q1_budget.xlsx → Q1_budget.xlsx.bin2.
• Renaming Convention:

  1. The original file is overwritten with encrypted data.
  2. A new file of identical name plus .bin2 is created.
  3. Older samples leave the original file in place with an extra .bin2 suffix; newer strains remove the original to save space. No e-mail addresses or ransom ID strings are injected into the filename itself.

2. Detection & Outbreak Timeline

• Approximate Start Date/Period: Malware-triaging services first identified samples of the “.bin2” strain in late July 2020. Active distribution spikes occurred in November 2020 and a second, larger wave from February to April 2021. Most recent confirmed infections cluster around June 2023, with small intermittent bursts thereafter.

3. Primary Attack Vectors

• Propagation Mechanisms:

  1. Insecure RDP – brute-force logins on exposed 3389/TCP endpoints, often via credential-stuffing lists.
  2. Email Phishing – macro-laden Word or Excel attachments (“Invoice-$$$.xlsm”, “Shipment-update.docx”).
  3. EternalBlue (CVE-2017-0144) and the BlueKeep RDP flaw (CVE-2019-0708) on unpatched Windows 7/Server 2008 systems.
  4. Compromised Software-Updater Channels – fake Adobe Flash Player updates pushed through watering-hole sites and search-result poisoning.
  5. Drive-by Downloads – via the Fallout and RIG exploit kits when visitors run outdated browsers/Java.

Key early indicators of Bin2 intrusion logs:
– %SystemRoot%\System32\unsecapp2.exe (dropped copy)
– Persistence via HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SecBinService value.

Remediation & Recovery Strategies

1. Prevention

✔ Eliminate RDP exposure: disable 3389 on the edge, enforce VPN + MFA for remote access.
✔ Segment critical networks (VLAN/ACL) and deploy host firewalls denying SMB 445 egress between user segments.
✔ Apply Microsoft patches KB4457144 (EternalBlue), KB4499175 (BlueKeep), and cumulative security roll-ups dated March 2021 or later.
✔ Restrict Office macro execution: group-policy to “block macros from the Internet,” enable only signed macros.
✔ Enforce application allow-listing via Windows Defender Application Control or third-party EDR.
✔ Maintain offline, air-gapped backups with 3-2-1 strategy and periodic restore drills.

2. Removal – Clean-up Playbook

  1. Isolate: physically unplug the host or disable its switch port; disable Wi-Fi/Bluetooth.
  2. Identify: open Task Manager → Details → look for unsecapp2.exe, system_sync.exe, or bin2.exe. Note location (%TEMP%, %APPDATA%\SecBin).
  3. Boot to Safe Mode (with networking disabled).
  4. Delete malware files:
  • %APPDATA%\SecBin\ entire folder (propagation script & ransom note)
  • %SystemRoot%\System32\unsecapp2.exe – compare hash against baseline.
  1. Wipe scheduled tasks and registry keys: 
   reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Run" /v SecBinService /f
   schtasks /delete /tn "SecBin Helper" /f
  1. Run reputable AV/EDR scan (Windows Defender offline scan, Malwarebytes, Sophos HitmanPro) to retrieve additional droppers.
  2. Patch and harden: apply OS + application updates; change any reused credentials.

3. File Decryption & Recovery

• Recovery Feasibility:
– Bin2 is based on an AES-256 + RSA-2048 hybrid model. Private keys are generated per victim and kept only on the attackers’ server. No free decryptor exists at the time of writing (June 2024).
– If you have uninfected/offline backups or Volume Shadow Copies (check vssadmin list shadows), restore from those.
– Shadow copies:

vssadmin list shadows
(Pick a valid shadow ID)
robocopy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy8\Users\Me\Documents X:\Restore\ /E

– You may upload a pair of original-file.bin2 + non-encrypted twin to NoMoreRansom.org for re-evaluation if a decryptor is released later.
• Essential Tools & Patches:

  • Microsoft Security Update Catalog – patch universe 4457144, 4499175, and all subsequent cumulative updates.
  • Kaspersky AVDecrypt tool (current version 3.0.1.251) – signature continuously updated; feed file pairs to test whether decryption is possible.
  • CISA “StopRansomware Toolset” – preemptive hardening script Harden-Windows-Secure-Baseline.xlsx.

4. Other Critical Information

• Unique Characteristics:
– Bin2 is the first known strain that explicitly stops Windows Background Intelligent Transfer Service (BITS) to hinder subsequent patch downloads.
– It also encrypts SQL Server database data + transaction logs in RAM first, terminating SQL services (sqlservr.exe) to maximize data loss and prevent fast roll-forwards. Privileged DB backups are often missed by endpoint protection that scans filesystem IO only.
– Adds an extra layer of OTP-based staging – the initial dropper fetches stage-2 only after receiving a 9-digit code from its C2 server; this helps it bypass static sandbox signatures.
• Broader Impact:
– Widely affected mid-sized healthcare and accounting firms (ICD-10 back-office environments) who deferred patching BlueKeep.
– Average ransom demand: 4.5 BTC (≈ US$120-150 k in 2021 spikes) with public-data dumping threats on “dark-leaks.net”.
– Multiple downstream victims lost HIPAA data; some faced regulatory fines > ransom itself.

Stay vigilant: threat actors recycle the Bin2 framework under different TLDs; always correlate indicators (filename hashes, registry mutex BinMutx2020!) against MITRE ATT&CK for up-to-date defenses.