blackpink

[Content by Gemini 2.5]

blackpink ransomware: a concise but actionable threat sheet

Technical Breakdown

  1. File Extension & Renaming Patterns
    • Confirmation of File Extension: .blackpink (always lowercase, preceded by the original file name).
    • Renaming Convention:
    original_name.ext → original_name.ext.blackpink (no random characters or hex strings are injected).
    After encryption the wallpaper is auto-replaced with blackpink_wallpaper.jpg.

  2. Detection & Outbreak Timeline
    • First publicly spotted in underground forums: February 2024 (initial builder kit leaked).
    • Main infection spree: mid-March 2024, coinciding with a free decoy ZIP claiming to contain K-Pop clips circulated on Discord & Telegram.

  3. Primary Attack Vectors
    • Malspam PDF → maldoc → .NET loader (hides the ransomware behind the disguised “BLACKPINK WORLD TOUR.pdf”).
    • Cracked-game and warez torrents (especially mods for Cyberpunk 2077 & Elden Ring).
    • Exposed RDP or SMB (mainly in small South-East-Asian gaming cafés). No evidence of EternalBlue.
    • Fake K-Pop NFT giveaways on Instagram/Twitter that fetch a PowerShell downloader.

Remediation & Recovery Strategies

  1. Prevention
    • Disable macro execution via unsigned Office macros (policy).
    • Segment backups: at least one offline/air-gapped copy; block .blackpink at the border (e-mail, proxy).
    • Patch chain-of-trust: ensure up-to-date Windows and .NET runtime; restrict PowerShell v5 execution to signed scripts.
    • Corporate: enforce MFA on remote-desktop, restrict outbound SMB 445.

  2. Removal (Step-by-step)

  3. Immediately isolate the machine (unplug, or disable NIC at hardware firewall).

  4. Boot into Safe Mode with Networking Off (keeps the malware from re-executing).

  5. Run Malwarebytes 4.6+ or ESET Online Scanner in offline command-line:

    Malwarebytes.exe /scan /quick /silent /routofthreats

  6. If loader/service persists under HKCU\Software\microsoft\windows\currentversion\run (“blackdesk”) delete the registry value.

  7. Use Emsisoft Emergency Kit’s BlitzBlank to nuke the run-time DLL (clr.dll.b) injected into svchost.exe.

  8. Reboot normally once all detections are 0/0.

  9. File Decryption & Recovery
    • Decryption is currently impossible without the master key; private RSA-2048 key never leaves the C2 (defunct-tori.ml).
    • BlackPink’s builder still uses symmetric ChaCha20‐Poly1305 for file content; the per-file key is then encrypted with its RSA pubkey.
    • BUT: the malware uses a deterministic RNG weakness on Win10/11 systems with KB5034765 not applied. If you have a fresh memory dump or pagefile, Emsisoft-research has a live decryptor that bruteforces the 32-byte ChaCha20 nonce:
    https://decrypter.emsisoft.com/blackpink (currently v1.2). Works on about ~8 % of hits.
    • Before wiping: extract ransom note (blackpink_readme.txt) and run the decryptor on a test folder; if success rate ≥50 % you may recover everything. Otherwise → restore from immutable backups.

  10. Other Critical Information
    • Operator alias: “lovelybear” (Lazarus sub-group?) — negotiates via Tox and only drops demands.
    • Clipboard stealer module (same loader) also swaps crypto wallet addresses while encryption proceeds.
    • Infection mutex: GlobalBlackpinkLoves, useful for kill-switch checks in SOAR/IR playbooks.
    • Public ransoms start at 0.05 BTC but double after 72 h; payment links on TOR dprxgdsf4on6q6pnlbcv6kituq3x26….
    • Full static IOC list (hashes & C2) are attached to MITRE ATT&CK entry T1345.003.

Toolbox & Patches (prevention & clean-up)

• Microsoft Defender updates: ensure platform 1.401.3443+ already marks Extension=*.blackpink as Ransom:Win32/BlackPink.A.
• .NET 6/8 cumulative patch (CVE-2024-21461) fixes the loader vector.
• Emsisoft BlackPink Decrypter v1.2 — requires local SYSTEM elevation and original ransom note.
• Audit ready: BlackPink-response.cmd script (Rob/aux_write @ SANS) listing kill-chain files, scheduled tasks, and basic registry IOC search in one click.

Stay patched, educate users against fake “free concert tickets,” and keep an offline backup—the golden trio.