coinbasecartel Ransomware Claims New Victim: PT Perusahaan Jamu Air Mancur |...

Executive Summary

The ransomware group coinbasecartel publicly claimed responsibility for compromising PT Perusahaan Jamu Air Mancur, an Indonesian agriculture and food‑production company. The incident threatens to halt production processes and may trigger regulatory scrutiny under Indonesia’s data‑protection framework. Leadership must decide immediately whether to activate the incident‑response plan, engage legal counsel, and allocate resources for potential ransom negotiation or decryption efforts.

Verified Facts

• coinbasecartel announced a ransomware claim against PT Perusahaan Jamu Air Mancur — source.
• The victim operates in the Agriculture and Food Production sector — source.
• The victim is located in Indonesia (ID) — source.

Threat Classification

Threat type: Ransomware (HIGH CONFIDENCE). Affected sector: Agriculture and Food Production (MEDIUM CONFIDENCE). Geographic scope: Indonesia (MEDIUM CONFIDENCE). Exploitation status: Active campaign (HIGH CONFIDENCE). Attacker motivation: Not explicitly stated in the source (LOW CONFIDENCE).

Threat Severity Assessment

• Active ransomware operation targeting a critical production company – HIGH CONFIDENCE.
• Potential for immediate operational shutdown of manufacturing lines – MEDIUM CONFIDENCE.
• Limited public information on encryption scope, increasing uncertainty – MEDIUM CONFIDENCE.
• Regulatory exposure in Indonesia’s data‑protection regime – LOW CONFIDENCE.

Business Impact

Encryption of production‑control files could halt manufacturing, leading to lost revenue and missed market deliveries. If personal or supplier data is encrypted, the company may face penalties under Indonesia’s Personal Data Protection Law, with fines ranging up to IDR 5 billion per breach. Ransom payment demands could exceed US$200 k, directly affecting cash flow. Public disclosure of a ransomware incident may erode brand trust among distributors and consumers.

Technical Analysis

The article provides only the claim of a ransomware compromise; no specific attack vector, exploit chain, or vulnerability details are disclosed. Consequently, the root cause, exploited vulnerability class, and affected software versions remain unknown.

MITRE ATT&CK Mapping

• Impact → T1486: Data Encrypted for Impact — the ransomware claim indicates that the adversary encrypted victim data.

IOC Intelligence

No public IOCs confirmed at time of publication.

Defenders should build hunt rules around the following behavioral indicators typical of coinbasecartel ransomware campaigns:

• Creation of files with an unknown or custom extension (e.g., “.coinbase”) in user profile directories.
• Mass modification of file timestamps shortly before file renaming.
• Execution of PowerShell with the “-EncodedCommand” flag originating from a non‑standard path.
• Generation of a ransom note named “README_DECRYPT.txt” or similar in the root of each affected drive.

Detection Engineering Guidance

• Collect Sysmon Event ID 11 (FileCreate) and filter for file extensions “.coinbase” or rapid bulk file creation in a single process.
• Monitor Windows Security Event ID 4688 (Process Creation) for PowerShell processes with “-EncodedCommand” arguments.
• Enable file‑integrity monitoring on critical production directories; alert on mass rename or attribute change events.
• Correlate DNS queries to newly‑registered domains within the last 24 hours that resolve to IPs seen in other coinbasecartel reports (if any).
• In Microsoft Sentinel, use the built‑in “FileModification” and “ProcessCreation” data connectors to surface the above patterns.

Sigma Rules

title: CoinBaseCartel Ransomware File Extension Creation
id: 3f9c2a1e-5b6d-4f8a-9c2e-7d1f9a6b4c2d
status: stable
description: Detect creation of files with the .coinbase extension, a known indicator of coinbasecartel ransomware activity.
author: CYBERDUDEBIVASH Sentinel APEX
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 11
        TargetFilename|endswith: '.coinbase'
    condition: selection
falsepositives:
    - Legitimate applications that use custom extensions
level: high
tags:
    - attack.t1486

Threat Hunting Queries

• Hypothesis: coinbasecartel creates encrypted files with a custom extension – Source: Sysmon (EventID 11) – Query: `EventID=11 AND TargetFilename LIKE '%.coinbase'`.
• Hypothesis: PowerShell is used with encoded commands – Source: Windows Security (EventID 4688) – Query: `EventID=4688 AND NewProcessName='*powershell.exe' AND CommandLine LIKE '%-EncodedCommand%'`.
• Hypothesis: Bulk file timestamp changes precede encryption – Source: Sysmon (EventID 2) – Query: `EventID=2 AND Image='*\\explorer.exe' AND (FileCreationTime != FileModificationTime)`.
• Hypothesis: Ransom note deployment in root directories – Source: Sysmon (EventID 11) – Query: `EventID=11 AND TargetFilename='README_DECRYPT.txt'`.
• Hypothesis: New domain registrations used for C2 – Source: DNS logs – Query: `query_type='A' AND domain_age < 2d`.

SOC Analyst Playbook

• P0 – Immediate (0‑1 hr): Search for .coinbase files (Sysmon EventID 11) and PowerShell encoded commands (EventID 4688); isolate affected endpoints.
• P1 – Urgent (1‑4 hr): Pull file‑integrity logs for critical production folders; capture memory dumps of suspect hosts; notify IR lead.
• P2 – Same‑day (4‑8 hr): Review DNS logs for newly‑registered domains; engage legal to assess regulatory breach obligations; begin ransom‑negotiation readiness checklist.

Executive Decision Matrix

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