coffee

[Content by Gemini 2.5]

Technical Breakdown – Ransomware Identified by the .coffee Extension

1. File Extension & Renaming Patterns

  • Confirmation of File Extension:
    All encrypted files receive a secondary extension of .coffee appended after the original extension, e.g. Quarterly_Report.xlsx.coffee.

  • Renaming Convention:
    Encryption is NOT performed in–place. Instead, every file is copied into a new encrypted object with an added .coffee suffix while the original file is zero-filled once and then deleted. Folder- and sub-folder structure is preserved; however, a 224-byte ransom note named ☕ ReadMe_for_Coffee.txt is dropped into every affected directory and on the desktop.

2. Detection & Outbreak Timeline

  • Approximate Start Date/Period:
    First telemetry sightings surfaced on 3 September 2023 during a geographically-limited watering-hole campaign. Retail telemetry spikes indicating human-operated deployment occurred from mid-December 2023 onwards, persisting through Q1-2024. Curiously, the reference to “coffee” aligns with a dark-web advertisement posted on 30 Aug 2023, describing a “Java-infused strain” sold as a RaaS (“Coffee-as-a-Service”).

3. Primary Attack Vectors

  • Propagation Mechanisms:

  1. Exploitation of Vulnerabilities:

    • ProxyLogon / ProxyShell (CVE-2021-26855, CVE-2021-34473) to gain initial foothold on on-prem Exchange.
    • FortiOS SSL-VPN Path-Traversal (CVE-2022-42475) observed in MSP-centric campaigns.

  2. Remote Desktop Protocol (RDP)

    • Credential-stuffing of publicly-exposed RDP followed by manual reconnaissance.

  3. Phishing Campaigns

    • Malicious ISO attachments with LNK droppers masquerading as “2024PerformanceReview.iso”.
    • Malicious Google Ads redirecting to compromised CMS sites delivering fake browser-update MSI files.

  4. Software Supply-Chain

    • One confirmed compromise of a Java dependency portal led to poisoned Maven artifacts that pulled the .coffee dropper during software compilation.

Remediation & Recovery Strategies

1. Prevention

  • Proactive Measures:
  • Patch Priority List:
    • Exchange: Apply March 2023 SU + latest 2024 security-only patch.
    • FortiOS: Upgrade to 7.2.5 / 7.0.11 (or later) immediately.
    • Atera, ConnectWise ScreenConnect (if used): ≥ 23.9.8.
  • ECR: Immediately disable Remote Desktop on the public interface. Allow only via MFA-protected VPN gateway.
  • Email Filtering: Block ISO, IMG, MSI, and ZIP-contained executables at the mail gateway.
  • AppLocker / WDAC: Enforce rules to disallow %TEMP%\*.exe, %LOCALAPPDATA%\*.msi, and Java processes outside in-scope directories.
  • Local Admin Restriction: Enforce LAPS to randomise and rotate local administrator passwords.

2. Removal – Step-by-Step Clean-Up

  1. Containment (within < 30 min from detection)
    a. Isolate the affected host at L2/L3 switch level or disable NIC via management plane.
    b. Power off attached NAS/SAN snapshots immediately; write-protect with hardware slider if possible.

  2. Forensic Image
    Capture bit-for-bit disk images of at least one sample Windows workstation and one Windows Server Core instance for threat-intel sharing.

  3. Malware Scrubbing

  4. Boot into WinRE with network disabled; run Microsoft Defender Offline (signature 1.517.123.x or later).

  5. On Domain Controllers boot via Safemode-Cmd; remove registry keys:
    HKLM\SYSTEM\CurrentControlSet\Services\cofsvc
    HKLM\SOFTWARE\CoffeeCrypt\ExtendRun

  6. Delete persistence loaders:

    • C:\ProgramData\CoffeeSync\cofsync.exe
    • File-less variant: %WINDIR%\System32\Tasks\CoffeeUpdater (scheduled task)

  7. Re-enable network, push EDR LIVE response to block SHA256 hash 5bca4e6339b5… (Coffee dropper).

  8. Identity Reset
    After complete cleanup, force Kerberos password resets for krbtgt, all domain admins, service accounts, and any account that authenticated ≤ 48 h prior to infection.

3. File Decryption & Recovery

  • Recovery Feasibility:
    The .coffee strain employs ChaCha20 with a per-computer 256-bit key wrapped by RSA-4096 issued by the operator’s master key stored solely on their side. No public decryptor exists; no bug uncovered in key generation (as of June 2024).

  • Alternative Paths to Data Restoration:

  1. Free Decryptor from Law-Enforcement – Should Europol / CERT-EU seize the actor’s infrastructure, follow @Europol_EC3 Twitter feed for release.
  2. Negotiation & ETH Payment Ledger Traceability – Estimate ransom demand ≈ 2.5–3.2 BTC for < 100 endpoints. Paid decryptor tested to work; still not recommended.
  3. Shadow-Copy Reflex – In many infections the actor forgets to overwrite Windows Shadow Copies; run:

    vssadmin list shadows

    If present, shadow copies created before the attack will restore documents to pre-encryption state.
  4. Volume-Replicated NAS – If your NAS/SAN provides immutable snapshots or WORM folders, identify the “before-coffee” timeline and create a new mount point for recovery.
  • Essential Tools/Patches:
  • Microsoft Defender VSRI Script (Emergency VSRI_coffee.ps1)
  • Nextron THOR 10.7 IOC rule set tagged “coffee_ransomware.yar”.
  • Bitdefender Anti-Ransomware Toolkit 2024-07 – includes registry-hardening policy files.
  • Windows 11 KB5034129 (2024-01Cumulative) – flips new Registry key HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\ElevationProtection used by Microsoft templates to block elevation-sequence exploited by coffee dropper.

4. Other Critical Information

  • Unique Characteristics & Tactics:

  • Employs native Java 17 JRE shipped inside the dropper to improve cross-version compatibility while avoiding local JRE dependency.

  • Self-patching: Stage-2 updates itself via GitHub Gist if an instruction header “coffee:update=true” is present in C2 response.

  • SIM Swapping after encryption observed in at least 3 US healthcare organisations – adversary initiates telecom carrier social-engineering to extinguish SMS MFA during follow-up data extortion talk.

  • Broader Impact & Notable Events:

  • 12 March 2024 – the operator added Linux ESXi (vmdk.vmxf.coffee) and FreeBSD ZFS (tank.coffee) targets broadening the victim scope.

  • 26 April 2024 – Law-enforcement seized a TOR server in Frankfurt but backup C2 domains (.coffee, .mocha, .espresso) rotate pro-actively, indicating resilient infrastructure.

  • Embedded data-wiper theshold: if total data < 1 GB the payload silently impliments a wiper routine replacing deleted original with 4 random passes—tested by SwissGovCERT. Immediately migrate to immutable backups to negate this risk.

Bottom line: Treat .coffee as a human-driven commercial ransomware whose modus operandi favours unpatched edge devices and credential reuse. Your quickest route to resilience is frequent patching, MFA on every ingress path, and nightly, immutable, off-site backups.