malware-triage-ir-respond

| | Malware Family | Classification of malware variants sharing code, infrastructure, or behavior patterns (e.g., Qakbot, Emotet, Cobalt Strike) | | Process Hollowing | Technique where malware creates a legitimate process in a suspended state, replaces its memory with malicious code, then resumes execution | | Beacon | Periodic network communication from malware to its C2 server, typically with a set interval and jitter for detection evasion | | Dropper | Initial malware component that downloads or unpacks the primary payload; often delivered via phishing | | Persistence Mechanism | Method used by malware to survive system reboots (registry run keys, scheduled tasks, services, WMI event subscriptions) | | IOC (Indicator of Compromise) | Observable artifact such as file hash, IP address, domain, or registry key that indicates malware presence |

Tools & Systems

• CrowdStrike Falcon / Microsoft Defender for Endpoint: EDR platforms for detection, containment, and threat hunting
• ANY.RUN / Joe Sandbox: Interactive malware sandboxes for dynamic behavioral analysis
• VirusTotal / MalwareBazaar: Malware intelligence platforms for sample identification and IOC enrichment
• KAPE (Kroll Artifact Parser and Extractor): Forensic triage tool for rapid artifact collection from infected endpoints
• YARA: Pattern-matching engine for creating custom malware detection rules based on observed indicators

Common Scenarios

Scenario: Emotet Loader Leading to Cobalt Strike Deployment

Context: EDR detects a macro-enabled document that spawns PowerShell, downloads an Emotet DLL, which subsequently loads a Cobalt Strike beacon. Three hosts are infected within 45 minutes.

Approach:

1. Immediately isolate all three hosts and block C2 IPs at the perimeter
2. Search email gateway for all recipients of the original phishing email and quarantine it
3. Sweep all endpoints for the Emotet DLL hash and Cobalt Strike beacon indicators
4. Analyze the Cobalt Strike beacon configuration to extract watermark, C2 profile, and staging URLs
5. Check for credential harvesting (Mimikatz/LSASS dump) and lateral movement artifacts
6. Eradicate all malware artifacts and reset credentials for affected users

Pitfalls:

• Focusing only on Emotet and missing the Cobalt Strike second-stage payload
• Failing to extract and block the Cobalt Strike Malleable C2 profile indicators
• Not checking for additional persistence beyond the initial detection (Emotet often installs multiple backup persistence mechanisms)

Output Format

MALWARE INCIDENT RESPONSE REPORT
=================================
Incident:         INC-2025-1547
Malware Family:   Qakbot (variant: Obama265)
Delivery Vector:  Spearphishing attachment (Invoice-Nov2025.docm)
First Detection:  2025-11-15T14:23:17Z
Scope:            4 endpoints confirmed infected

INFECTION TIMELINE
14:18 UTC - Phishing email received by jsmith@corp.example.com
14:19 UTC - Macro executed in WINWORD.EXE
14:20 UTC - PowerShell downloads update.exe from staging server
14:21 UTC - update.exe establishes persistence (Scheduled Task)
14:23 UTC - C2 beacon initiated to 185.220.101[.]42
14:35 UTC - Lateral spread to WKSTN-087 via stolen credentials
14:42 UTC - EDR detection fires, SOC alerted

IOCs EXTRACTED
File Hashes:  [SHA-256 list]
C2 Domains:   [domain list]
C2 IPs:       [IP list]
File Paths:   [artifact paths]

ERADICATION STATUS
[x] All malware artifacts removed from 4 hosts
[x] Persistence mechanisms deleted
[x] C2 infrastructure blocked
[x] Compromised credentials reset
[x] Email quarantined from all mailboxes

RECOMMENDATIONS
1. Deploy YARA rule for Qakbot variant detection
2. Block macro execution in documents from external senders
3. Implement application whitelisting on finance workstations