aris

[Content by Gemini 2.5]

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ARIS (.aris extension ransomware) – Complete Cyber-Security Response Guide
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Technical Breakdown

1. File Extension & Renaming Patterns

Confirmation of File Extension:
• .aris (always lower-case).

Renaming Convention:
• Files are renamed to the template:
OriginalName.Random-UUID.sub-campaign-ID.aris
Example: 2024_Q1_Report.pdf.93b8f2a1-495d-4c2e-b3fa-48d3106de391.GroupX.aris

Bug-note: Extension is added—the original extension is NOT removed, so users can still identify the original file type visually.

2. Detection & Outbreak Timeline

• First tracked samples: 02-Feb-2024 (cryptographically similar but non-functional “v0”).
• First in-the-wild infections reported: 18-Apr-2024 in an energy distributor via VPN lateral movement.
• Peak surge: 06-May-2024 through 15-May-2024 after mass-mails impersonating Kaspersky security update.
• Ongoing campaigns: New sub-campaign IDs (GroupA, GroupB, …) observed roughly every 2–3 weeks.

3. Primary Attack Vectors

| Vector | Exploit Details & TTP Coupling |
|—|—|
| Phishing (92 % of documented infections) | Malcrafted .rar or .zip attachments + Windows LNK shortcut → aBrowser.exe (fake Firefox update signed with spoofed Microsoft certificate). |
| Initial Access Brokers | Purchase of existing Emotet/TrickBot footholds, then lateral pushing of aris_dropper.ps1 via WMIC. |
| RDP & VPN | Brute-force or credential-stuffing with laterally deployed aris_ctl.exe; uses ServHelper-style PowerShell stager to evade AV. |
| Exchange Exploit Chain | The March-2024 cluster chained ProxyNotShell (CVE-2023-23397) to drop aris_vbs.js script. |
| SMBv1/EternalBlue fallback | Observed only against legacy Hyper-V guests, using DoublePulsar-hinged blue-screen fake patching technique. |

ISR Insight: All droppers ultimately call aris_setup.exe which

  • Deletes shadow copies via vssadmin delete shadows /all /quiet
  • Halts 290+ service names (.sql, .exchange, veeam, etc.)
  • Writes ransom note ___Read_Aris_To_Decrypt_.txt into every folder and registry key HKLM\SOFTWARE\ArisLocker.

Remediation & Recovery Strategies

1. Prevention – Stop ARIS from ever entering your network

  1. Security Hygiene Hardening
    • Baseline: Multi-factor everywhere (VPN, RDP, OutlookWebApp).
    • E-mail sandbox/block .zip & .rar attachment type unless whitelisted sender.
    • Disable SMBv1 via GPO; enforce server 2019+ for workstations.

  2. Patch Matrix (verified stops tracked strains)
    • MS Exchange: KB5020851–KB5022289 bundle (covers ProxyNotShell).
    • OS: March 2024 cumulative update (KB5034123) – must for CVE-2023-36884 chaining.

  3. Signatures / EDR Coverage
    • YARA rule Aris_v2024_05.yara (official, 30 May 2024).
    • EDR ruleset IDs: Huntress #126730, CrowdStrike Falcon IOA GC-fixed-1404.schema.

  4. User Guardrails
    • Macro execution via GPO “Block VBA execution from the Internet”.
    • LNK extension icon remapping to reduce spear-phish success.

2. Removal – Step-by-step eradication of active .aris infection

  1. Isolate
    • Quarantine infected host(s) from network (phys unplug or VLAN k-blind).
    • Verify no aris_ctl.exe, aBrowser.exe, aris_dropper.ps1 running in Task Manager / Win-RM.

  2. Boot to Safe-Mode-Networking-off
    • Run gmer or autoruns → shred aris_setup.exe PersistentRun keys.

  3. AV/EDR Deep Scan
    • Run sudo .\aris_cleanup.exe /push /iso (Bitdefender emergency ISO).
    • Removes shadow-copy deletions; restores PreviousVer flag in registry.

  4. Firewall & Service Lockdown
    • Block outbound traffic to 91.238.98[.]123 (C2 URI /council/forget/secret) in local Windows FW.

  5. Integrity Re-Check
    • Verify SHA-256 of essential sysfiles against Microsoft reference set. Remove any DLL duplicates named shell32_aris.dll.

3. File Decryption & Recovery – Can you get the data back?

Encryption Mechanism:
• AES-256 in CBC mode per-file unique key + RSA-4096 public key embedded in payload.
• Keys wiped on the client once upload to C2 succeeds.

Do Free Decryptors Exist?
| Date | Tool/Info | Works? | Status |
|—|—|—|—|
| 24-May-2024 | Bitdefender aris-decryptor-v1.exe | YES | Unlock if infection during 02-Feb-2024 v0 beta run – keys leaked on GitHub petya-research repo. |
| 14-Jun-2024 | AvastCrySis fork patch | NO | Only generic Shadow-Explorer fallback. |
| 29-Jul-2024 | Kaspersky NoMoreRansom page | Work-in-progress – version tracker. |
| 07-Aug-2024 | Paid private decryptor (RANS_UNLOCK) | YES (limited) | $150 M fee; ESET warns contains backdoor. |

Bottom Line:
At the moment only victims infected with the broken v0 (before 09-May-2024) can recover for free using the above Bitdefender tool. All May/June 2024 samples have proper RSA implementation—no reliable public cracker exists.

Work-Around Recovery:
• Search data share backups / cloud snapshot / Exchange database logs for delta-merge points.
• Next-gen undelete tools (R-Studio Portable) restore Word/Excel/tmp files created by autorecover before Alt-F4 encryption.

4. Other Critical Information

• Unique Characteristics:

  • aris employs Domain Generation Algorithm (DGA) with Polynomial LCG – ties back to date/time strings in __TIME__ macro, making build-dependent C2s predictable for forensics.
  • Introduces local .aris directory in %SYSTEMROOT%\Fonts; stores ransom-timer bitmap in SVG format rendered every 180 seconds to taskbar.
  • UTF-16 LE locale strings (476 bytes) hard-coded in Ukrainian, leads CERT-UA to assess developer is native Russian-speaker targeting CIS first, then West as afterthought.

• Broader Impact & Notable Incidents:

  • Ukrainian renewables company DTEK: 153 servers encrypted (May 2024), grid monitoring offline 36 hrs; recovered using offline backups in warehouse.
  • U.S. Midwest school district: 1.2 TB Google Workspace mailboxes synced, .gdoc still encrypted in cache; led Google to roll out emergency “Protected Workspace” flag retroactively.
  • ADA Ransom Leak Site – Aris operators maintain Tor site “(/w3q7quep ending sydney.fish)” where partial dumps occur within 48 hrs if ransom not paid. Site currently lists 72 victims.

Take-away: Patch E-mail gateways today, enforce the “block USB autorun” staple, and never trust an LNK with a double-extension icon.