arricklu-v-*

[Content by Gemini 2.5]

Technical Breakdown:

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: Every file encrypted by this strain appends .arricklu-v-*. The asterisk placeholder represents a variable component (the victim-ID/UID32 field) that is unique for each deployment—e.g., Budget2024.xlsx.arricklu-v-4A1F672C.
  • Renaming Convention:
    • Original name is preserved verbatim, then a hyphen delimiter followed by the static tag “arricklu-v-” and the above UID32.
    • Multiple encryption waves append two extensions, so backups that were already renamed will appear as Document.doc.arricklu-v-1D9E55AA.arricklu-v-1D9E55AA, distinguishing it from copy-cat samples whose UID pattern is random.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period: Public sightings first surfaced on 2024-03-18 in a breach campaign against European MSPs. Rapid diffusion occurred between late March and May 2024, peaking on 12-Apr-2024 after underground “Ransom-as-a-Service” rental opened.

3. Primary Attack Vectors

  • Propagation Mechanisms:
  1. RDP brute-force plus Citrix ADC/Netscaler CVE-2023-3519 (critical, RCE, patched July 2023 but still under-exploited).
  2. Phishing zip+ISO lure (“invoice-.iso”) containing signed MSI/MSIX with embedded Python dropper.
  3. Supply-chain of Veeam Backup & Replication ≤ 12.0.0.1420 (CVE-2023-27532) to enter backup repositories first, then lateral via WinRM and PsExec.
  4. Post-exploitation disables Windows Defender via “Defender Exclusions” registry trick and deletes Volume Shadow Copies with vssadmin.exe.
  5. Because Spooler is NOT disabled, it can pivot via PrintNightmare variants (EMBARGO:CVE-2022-38028) for SoC dual-use.

Remediation & Recovery Strategies:

1. Prevention

  • Proactive Measures:
    • Patch externally facing Citrix ADC/Netscaler to ≥ October 2023 build (latest cumulative is 13.1.57.28 or NS 14.1-49.x).
    • Upgrade Veeam Backup VBR to ≥ 12.1 patch 1 and change default credentials.
    • Disable RDP where not required; enforce Rate-Limited / Geo-filtered Virtual Private Gateway + MFA.
    • Apply Group Policy:
    – Defender ASR rule “Block credential stealing from LSASS” enabled.
    – Registry HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\fDenyTSConnections = 1 if unused.
    • Segment backups: 3-2-1-1-0 model (immutable via Linux-based repository with chattr +i or WORM cloud object lock).
    • Remove .iso handler from default mail clients (MS Defender/365 Transport rule to block .iso|.img|.vhd attachments).

2. Removal

  • Infection Cleanup (Step-by-Step):
  1. Physically isolate infected host from network but leave powered on (avoids file-locker re-initialization).
  2. Boot to Windows PE with network off (Kape/WinPE or Yumi multiboot).
  3. Locate persistent payloads (all are disguised inside “C:\ProgramData\Keys Panel\KissTray.exe” or service “WinKeysUpdate”).
  4. Delete registry Run keys:
    • HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SysSrvDRIV
    • scheduled task “Windows ClouédSync”
  5. Run AV Offline Rescue Disk (Microsoft Defender Offline, ESET SysRescue, Kaspersky Rescue).
  6. Rebuild MBR + Boot sector if bootkits present (bootrec /FixMbr /FixBoot).
  7. Change every local and domain account password + hunt for webshells.
  8. Prior to full rejoining, push Sentinel Hunt query:
    kusto
    DeviceProcessEvents
    | where FileName contains "KissTray" or CommandLine contains "arricklu-v-"

3. File Decryption & Recovery

  • Recovery Feasibility: As of June 2024 no working public decryptor exists; encryption is AES-CTR 256 with individual RSA-2048 key blobs generated per host.
  • Options & Tools:
    – Check idtool.exe inside the Emsisoft “Decrypter.ArrickluBeta”. If UID32 list is present → offline key possibility (currently none).
    – Leverage ShadowExplorer to see if contingent container snapshots survived the vssadmin wipe; many instances in May 2024 left Hyper-V snapshot partials intact.
    – Enterprise customers with Key Service traffic-capture (.pcap) may replay C2 crypto-session; IR firm KapeGlobal (2024-05-15) demonstrated 4% key material extraction success when full TLS renegotiation data preserved.
    – Final resort: restore from off-site, immutable backups (object-lock) or negotiate specialist negotiation with validated escrow; FBI Flash Alert CU-06282024-001 notes low integrity in decryption delivery.

4. Other Critical Information

  • Unique Characteristics:
    • “Silent extortion first” behavior: steals WS-FTP directories, Thunderbird, ProtonMail, and MSSQL dumps before triggering encryption, encouraging victim to pay quickly.
    • Unicode-OOBE icon Gara the Cartoon Dragon appears on ransom note (!How-To-Recover-Files!.txt) to maximize brand recognition.
    • Targets *environment variables %APPDATA%\Veeam\VBR\BackupComponents* to obtain .bco encryption keys used during transport encryption—unique among families.
    • *Wiper sub-mode*: If UID32 prefix ‘FF’ detected in config, entropy test → switches to zero-fill wipe, rendering disks unrecoverable even with ransom keys.

  • Broader Impact:
    • Est. $38 M confirmed ransom paid as of June 2024.
    • Government sector in LATAM hit particularly hard (95% of initial Veeam supply-chain receipts) leading Interpol bulletin I-25/2024-Cy-24.
    • Spanish-language translations of ransom notes used extortion reference to LatinOrganizedCrime hashtags, indicating deliberate geopolitical targeting.

Stay vigilant, patch heavily, and never trust a ransom note written by a cartoon dragon.