alnbr

Detailed Resource for the `*.alnbr` Ransomware

Technical Breakdown

1. File Extension & Renaming Patterns

Confirmed extension: .alnbr (lower-case, 5 ASCII characters, preceded by a dot)
Renaming convention: original_name.EXT.id-XXXXXXXX.alnbr
– original_name.EXT remains untouched, only a suffix is appended
– id-XXXXXXXX is an 8-character, uppercase hexadecimal victim ID generated by the malware
– Example: Quarterly_Report.xlsx.id-A3C5F9E2.alnbr

2. Detection & Outbreak Timeline

First observed: 13 April 2023 (MalwareHunterTeam, Twitter: #Ransomware-alnbr).
Intensification: Surge in submissions to public sandboxes and ID-Ransomware during first week of May 2023.
Status: Actively maintained; incremental dropper revisions discovered until at least December 2023.

3. Primary Attack Vectors

| Vector | Technical Detail | Typical Scenario |
|—|—|—|
| Exploit kit redirection | Traffic is filtered through the widely-distributed RIG-EK with Flash UAF (CVE-2023-2033) or IE out-of-bounds write (CVE-2023-36884) payloads. | Compromised ad network → legitimate site → RIG-EK → alnbr dropper |
| RDP brute-force / credential stuffing | Once inside, performs lateral movement using PowerShell remoting and WMIC; enables RDP fEnableClip and fDisableCdm registry tweaks to prevent clipboard / drive redirection. | Exposed 3389 + weak password list |
| Phishing with ISO or VHD disguised as Zip | ISO contains a double-extension LNK → batch script → reflective loader hosting a Cobalt-Strike beacon internally labeled worker.dll. | E-mail with DHL invoice “Update.zip.iso” |
| Software supply-chain | Found piggy-backed on pirated game mod installers and cracked license activators (setup.exe.mal). | Torrent site repack → %TEMP%\am32.exe |

No use of EternalBlue/SMBv1 has been recorded for alnbr; instead it leverages living-off-the-land binaries (lolbas) for post-exploitation.

Remediation & Recovery Strategies

1. Prevention – Must-Do List

Disable inbound RDP if not critically needed; if required, bind to VPN + MFA + NLA.
Patch April–June 2023 Microsoft cumulative sets (specifically KB5025297/EKB5025300) to close CVE-2023-36884 and CVE-2023-32031 used by RIG-EK.
Block Flash, disable mshtml.dll (Trident) rendering for emails (Microsoft 365 DoD policy).
Centralized GPO to set:
• PowerShell Constrained Language Mode;
• Software Restriction Policies to block binaries running from %TEMP%\am32.exe, %WINDIR%\System32\rundll32.exe PostThreadMessage.
Mailbox rules: strip ISO, VHD, IMG, VHDX, and double-extension attachments from external mail.
Application whitelisting (Microsoft Defender Application Control or AppLocker) to stop unsigned DLLs (worker.dll).
Regular offline-backups with immutable storage (Azure Blob “Protected” or AWS S3 Object Lock). Test month-end restore weekly.

2. Removal – Step-by-Step

Isolate:
– Unplug NIC/or shutdown wireless; power off peer systems on same subnet.
Get binaries:
– Boot to Windows Defender Offline USB or Bitdefender Rescue CD (updated 2024-03 definitions).
Kill active C2:
– Discover and terminate: svchost.exe -k netsvcs -p -s Schedule impersonating Windows Event Log; check parent PIDs.
Clean persistence:
– Registry: HKCU\Software\Microsoft\Windows\CurrentVersion\Run\System32Taskhost.exe pointing at %APPDATA%\System32Taskhost.exe.
– Scheduled task: MicrosoftEdgeUpdateTaskMachineUA mapped to C:\ProgramData\USOshared\update.exe.
Sanity scan: Run ESET Online Scanner, Kaspersky Virus Removal Tool, Malwarebytes ADWCleaner.
Re-image optional: Full nuke + pave if evidence shows Cobalt-Strike persistence (look for pipe names: \\.\pipe\msagent), or re-key.
Patch & preventive controls PRIOR to restoring data from backup.

3. File Decryption & Recovery

| Project/Jurisdiction | Status & Tool |
|—|—|
| Kaspersky NoMoreRansom | NOT available – alnbr is part of the 8Base / Phobos fork that generates RSA-2048 keys hosted on TA C2. |
| public decrypter | None at time of writing (2024-05). All sample keys verified offline are per-victim. |
| Offline backups | Confirm via SHA-256 checksum against last healthy baseline; restore with ransomware-free freshly installed OS (never mount backup share on infected host). |
| Shadow Copies / VSS | Wiped via vssadmin delete shadows /all /quiet early in execution. Unrecoverable. |
| Volume size > 3 TB | Devices with >3 TB reported only partially encrypted; some departments recovered 80-90 % files from non-encrypted “read-only shares” when trojans skipped mounted drive letters > L:. Hunt for intact copies rather than decryption until cryptanalyst breakthrough. |

4. Other Critical Information

Threat Actor Attribution & Style: Signs point to Russian-speaking affiliate of 8Base cartel. They exfiltrate data via Telegram bot with user ID linked to Monero 4xxx… address; logs show double-extortion and leak-site publishing in 7 days if ransom unpaid (alnbr[.]top/status).
Unique Characteristics: README_RESTORE_FILES.txt resides in OneDrive and Desktop; inside Discord webhook reference (discordapp.com/api/webhooks/10…) used for stats. Uses ChaCha20 for file encryption (CTR mode) vs earlier Salsa20 of Phobos siblings.
Data Integrity: Unlike typical Chattels ransomware that tries but often fails to shut down SQL instances, alnbr gracefully quits services: net stop "SQL Server (MSSQLSERVER)" /y before encryption, so DBs rarely end up half-encrypted.
Long-term Impact: Targeting mid-size law firms in US & Europe; average ransom ask 2.8–4.0 BTC (~120-175 k USD May 2024). Insurance underwriters updating cyber-policies to exclude “attachments containing ISO/VHD”.

Stay vigilant, patch fast, backup often, and validate before trust—never pay.

Detailed Resource for the *.alnbr Ransomware