adobe.gefest

[Content by Gemini 2.5]

Adobe.Gefest Ransomware Deep-Dive & Recovery Playbook

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmation of File Extension: adobe.gefest (range-wide collector flag: .gefest with optional prefix adobe. depending on dropper branding).
  • Renaming Convention:
    Original → OriginalName.{ext}.adobe.gefest
    Note: if multiple infections occur, repeated .adobe.gefest chains may appear (rare, but indicative of an automated re-infection cycle).

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    • First public sightings: February 2023 via a small but sustained branch of IcedID dropper campaigns.
    • Peak expansion: June–August 2023 after integration into the stolen-build chain of the Phobos fork “Gefest Extortion-PiggyBack”.
    • Status Q1 2024: Still circulating modestly via loader-as-a-service kits but overshadowed by Akira and LockBit 3.0.

3. Primary Attack Vectors

| Mechanism | Details & Known Campaigns | Known CVE / Protocol |
|—|—|—|
| Phishing email bundles | ISO, VHD or 7-zip attachments containing LNK->MSI pivot chain dubbed “Invoice1220signed.iso”. | – |
| RDP brute spraying | Targets TCP/3389 exposed to internet; modules re-use cracked credentials from Raccoon-infostealer dumps. | – |
| Exploitation of ProxyNotShell & Exchange ProxyShell misconfigurations | Mass-scans for OWA/ECP endpoints; next payload is PowerShell dropper. | CVE-2022-41040, CVE-2022-41082 |
| Legitimate Update Abuse | Fake Adobe Acrobat/Reader updater (STDPDFUPD.exe) dropped by malvertising on fake “Adobe Reader update for Windows 11” pages. | – |
| Legacy SMB weaknesses | If one host is breached, LSASS dump → lateral WMI + PsExec spread. Enabled by SMBv1 still allowed on industrial networks. | EternalBlue source ports refined (EternalSynergy-SMB3) |

Remediation & Recovery Strategies

1. Prevention (Keep the door locked before the lockpick arrives)

  1. Patch everything:
    • Windows May 2023+ CU, Exchange March 2023 SU (kills ProxyNotShell).
    • Disable SMBv1 everywhere (Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol).
  2. Restrict RDP to jump-box/VPN only; enforce account lockout thresholds (<5 attempts) and NLA.
  3. E-mail hardening:
    • Filter ISO/VHD outbound.
    • Enhance attachment sandbox (e.g., Microsoft Defender SmartScreen/ATP® attachment detonation).
  4. Application-control allowlist (Applocker / WDAC) blocking unsigned STDPDFUPD.exe or MSI from %TEMP%.
  5. Endpoint-EDR agent rules: block memory injection via rundll32.exe calling Shell32.dll!ShellExecuteExW from below AppData.

2. Removal (Clean-up once locked down)

Full kill-chain elimination:

  1. Network Isolation: Isolate infected subnet from data-plane but maintain log flow for forensics.
  2. Kill running locker processes:
    • Quick find:
    powershell
    Get-Process | Where-Object {$_.ProcessName -like "*gefest*" -or $_.Path -like "*adobe*"} | Stop-Process -Force

    • Delete loader persistence:
    HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → STDPDFUPD and rundll32 “%AppData%\Systm.dll”,Start.
  3. Quarantine infector files: Check %AppData%, %ProgramData%\Adobe_x64, and C:\PerfLogs for Systm.dll, stdls.exe, “readerupdate*.exe” hashes.
  4. Fsutil raw access wipe & NTFS shadow purge block – ensuring ransomware has no chance to re-encrypt discovered Shadow Copies after restart.
  5. Reboot → rescan with offline (WinRE) AV boot utility (Defender Offline, Sophos PE32).

3. File Decryption & Recovery

| Status | Details |
|—|—|
| Decryption Feasible? | No free decryptor; symmetric AES-256 key wrapped by RSA-2048 (offline generated). No flaws found to date (July 2024). |
| Free Identifiable Samples / Reverse Check Tool | • EmsiSoft Ransomware Decrypter – Gefest Edition (released 2018 for the vanilla Phobos fork) → does NOT handle adobe.gefest keygen.
• Use ID-Ransomware (https://id-ransomware.malwarehunterteam.com/) to positively fingerprint before paying. |
| Practical Recovery Path | 1. Rebuild from known good backup ( immutable repository required).
2. Negotiation: average paid key is ~0.9–1.4 BTC; however extortion cabal stops replying after payment 30 % of time.
3. If bargaining is risk-averse, look into Partial File Carving with open-source PhotoRec for file fragments in docx/jpg. |

Recommended Tools/Patches

  • KB5020871 (Exchange ProxyNotShell patch).
  • Kaspersky – BitLocker Inspector to verify Crypto-integrity of shared volumes.
  • Microsoft Defender GPO – Attack-surface-reduction rules: “Block execution of potentially obfuscated scripts (Rule ID 5beb7efe-fd9a-4556-801d-275e5ffc04cc)”.

4. Other Critical Information

Unique Characteristics:

  1. Double-name encroach: retains the original extension among mutating chains – a side effect of its targeting logic for FileServers using file-type based encryption quota.
  2. Lateral-living-off-the-land: Uses internal Windows Defender exclusion lists (C:\PerfLogs\ & C:\ProgramData\SAP\work) to hide from real-time scans.
  3. Extortion webhook inside PDF metadata: embedded URL redirecting to Jabber chat to speed-up victim-to-gang contact post-detonation.

Broader Impact / Notable Incidents:

  • Paper Coating Supplier outage (EU): June 2023 incident attributed to adobe.gefest handled 15 TB of art plates – downtime 8 days, estimated $1.9 M loss (unpatched Exchange 2016 farm).
  • LatAm Municipality Finance Dept: Ransomware bridgehead via 6-year old Adobe Reader XI update prompt led to blackout of SAP S/4HANA box for 72h.

Immediate red flags for SOC:

  • Event ID 4768 kerberos pre-auth failure spikes → STDPDFUPD.exe fingerprint in cmdline.
  • Task Scheduler flurry creating AdobeReproUpdn36 job that merely runs powershell.exe -EncodedCommand base64 payload.

Stay patched, stay backed up, and maintain immutable writes to your off-site storage – the only reliable antidote to the adobe.gefest shake-down.