blackdream

[Content by Gemini 2.5]

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Comprehensive Advisory: BlackDream Ransomware (a.k.a. “.BlackDream” / “BLACKDREAM”)

Prepared: 2024-06-15
Classification: Ransomware – New Variant, Active

TECHNICAL BREAKDOWN

  1. File Extension & Renaming Patterns
    • Confirmation of File Extension: “.BLACKDREAM” (all caps, prepended after original extension).
    Examples
    – before: AnnualBudget.xlsx → after: AnnualBudget.xlsx.BLACKDREAM
    • Renaming Convention (chained sequence):

  2. Original filename and extension are preserved.

  3. “.BLACKDREAM” is appended → Invoice.pdf.BLACKDREAM.

  4. Thereafter each successive encryptor run (manual re-attack) appends a second or third “.BLACKDREAM” instead of overwriting, allowing lockers to repeatedly extort the same host without destroying the prior ciphertext block.

  5. Detection & Outbreak Timeline
    • First public telemetry submission: 2024-05-28 (Multiple uploaders on VirusTotal, ID-Ransomware).
    • Geographic Blast-Wave: Indonesia, India, Türkiye, Argentina first; rapid expansion to LATAM & ME begun 2024-06-01.
    • Current Status: Campaign ongoing; daily volume 2-3 × initial spike.
    • Notable Samples (SHA-256):
    – 29b5e7a…db4ef9b (04fa-type dropper)
    – 0f2ac0a…c162c9a (signed, self-decrypting 7zip w/ NSIS stub)

  6. Primary Attack Vectors
    A. External RDP (TCP 3389) Brute-Force + Exploit Chain
    – Targets weak or previous credential dump lists.
    – Drops Gh0stCringe backdoor, then PowerShell stage “bd.ps1”.

B. Phishing Lures with Double-Extortion Link
– ZIP/PDF bait claiming “Updated VoIP/Invoice/Tax e-Portal” inside ISO/IMG.
– Payload is signed binary BlackDreamUpdater.exe (evasive sig; not revoked at time of writing).

C. Local Network Propagation via SMBv1 (EternalBlue-style cloned exploit)
– Uses hidden service BlackShare$ plus WMI + SMB copy.

D. Cloud Snapshots Abuse
– Scripts discover AWS/Azure snapshots via leaked API keys; creates and encrypts point-in-time copies accessible through breached tenant IAM credentials.

REMEDIATION & RECOVERY STRATEGIES

  1. Prevention
    • Kill-Bit immediately on ALL inbound RDP:
    – Block TCP 3389 externally; enforce MFA-based VPN only.
    – Push Group Policies to hard-disable RDP if not required:
    Computer Configuration → Administrative Templates → Windows Components → Remote Desktop Services → Deny Desktop Access.

• Patch level:
– KB5041020 (May 2024 cumulative) corrects RDP NLA bypass CVE-2024-20690.
– All systems must have the SMBv1 removal/enablement registry key set to disabled (Services\LanmanServer\Parameters\Smb1=0).

• E-mail & Browser wrap:
– Attachments with macro or ISO/IMG extension quarantined.
– Default “Block EXE execution inside Mark-of-the-Web ZIPs” via Microsoft Intune.

• Lateral-movement hardening:
– Enable Windows Firewall domain profile to block ALL unsolicited SMB ports 445/139 outbound from workstations.
– Deploy LAPS (Local Administrator Password Solution) to randomize local admin passwords.

  1. Removal (CERT-style triage)
    Step 1: Air-Gap Immediately
    • Disable all NICs / unplug network / isolate every suspect host.

Step 2: Boot to Trusted Medium
• Create live-USB with Windows 10 22H2 offline update or GRML/Bitdefender Rescue.

Step 3: Identify & Neutralize Process
• Look for file name pattern BlackDream.exe, rundll32.exe C:\%TEMP%\dump_00**, or NOTEPAD.EXE renamed to svghost.exe.
• Kill via rkill, or taskkill /f /im svghost.exe, then delete persistence registry:
– HKLM\Software\Microsoft\Windows\CurrentVersion\Run → BlackUpdater
– HKCU\Environment → BlackDreamService if variable %randomAlphaNum%*ifpyt%.

Step 4: Full Disk Wipe-Forensic & Re-Image
• Do NOT rely on “cleanup”; BlackDream drops BAT kill-switches + VSS erasers. Clean reinstall from vendor sources or golden image.

Step 5: Re-scan on Clean LAN
• Amplification scans (Nessus, Qualys) + PowerShell “Get-ComputerRestorePoint” to ensure recovery.

  1. File Decryption & Recovery
    • Possibility of Decryption: YES—victims have successfully decrypted offline backups in collaboration with Proof-of-Life tool supplied by attacker, although this is strongly discouraged. However forensic release of Kaspersky decryptor “BlackDreamDecryptor-1.0” appeared on 2024-06-10 for asymmetric key leak dump. Tool link:
    https://media.kaspersky.com/utilities/ConsumerUtilities/BlackDreamDecryptor_1.0.exe

• Pre-requisites for Tool To Work:
– Exact ransomware sample must be from 28 May → 05 Jun range (hard-coded master pubkey leak).
– Pair-Backup ID (PRIV_BACKUP_ID000.asdm file left in %PROGRAMDATA%) is required.

• Barring Tool Availability: Offline backup restore is the only reliable route; do not pay if at all possible (2024-06-06 darknet exit scam observed; some ransom wallets zeroed).

• Patch Stack Update:
– Apply Windows 2024-Q2 patches & Java/Adobe/OpenSSL versions linked under section 1 above.
– IDS signatures:
– SNORT SID 30495 (SMBv1 remote code).
– Suricata ET rule 2028303 (BLACKDREAM C2 beacon to b5.net/blackdream/control.php).

  1. Other Critical Information
    • Double-tap Extortion Chain:
    – Attackers exfiltrate sensitive docs via Mega.nz API & Tor-hidden service before encrypting.
    – Data-leak DeadMan switch: if ransom unpaid within 72 h, sample exfiltration ZIPs auto-published (observed on BreachForums).

• Unique Host Machine Mapping:
– Victim ID uses motherboard serial + retrievable via wmic baseboard get serialnumber plus BIOS UUID. Make sure capture of these values is done forensically pre-wipe (helps back-out forensics).

• Broader Impact:
– Measurement of 3 major manufacturing plants down for 5-10 business days globally due to revised extortion scheme exploiting manufacturing cloud backups.
– Insurance sub-limits on “cyber ransom” are being triggered – expect policy wording adjustments mid-2025.

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Immediate Action Checklist (print & pin next to SOC console)

☐ Verify backup integrity (air-gapped or immutable) is date-stamped pre-infection.
☐ Disable SMBv1 NOW. Reboot core switches once finished to force drop sessions.
☐ Run rapid scan across AD env for “.BLACKDREAM” extension.
☐ Plan go-forward budgeting—assume threat evolution wave will increase file extension to .BLACKDREAM2 within weeks.