Files
T

3.5 KiB

Cobalt Strike Beacon Analysis Workflows

Workflow 1: PE File Configuration Extraction

[Suspicious PE] --> [Unpack if packed] --> [Locate .data section] --> [XOR Decrypt]
                                                                          |
                                                                          v
                                                                  [Parse TLV Config]
                                                                          |
                                                                          v
                                                              [Extract C2 Indicators]

Steps:

  1. Triage: Identify file as potential Cobalt Strike beacon via YARA or AV detection
  2. Unpacking: If packed, unpack using appropriate tool (UPX, custom unpacker)
  3. Section Analysis: Locate .data section containing XOR'd beacon code
  4. XOR Key Discovery: Try known keys (0x2e, 0x69) or brute-force 4-byte key
  5. Config Parsing: Parse decrypted TLV entries for C2 and operational settings
  6. IOC Extraction: Extract domains, IPs, URIs, user agents, watermarks

Workflow 2: Memory Dump Beacon Extraction

[Memory Dump] --> [Volatility3 malfind] --> [Dump Injected Regions] --> [Parse Config]
                                                                            |
                                                                            v
                                                                   [C2 Infrastructure Map]

Steps:

  1. Acquisition: Capture memory dump from compromised system
  2. Process Scan: Use Volatility3 to identify suspicious processes
  3. Injection Detection: Use malfind to find RWX memory regions
  4. Region Extraction: Dump injected memory regions to files
  5. Config Search: Scan dumps for beacon configuration signatures
  6. Infrastructure Mapping: Correlate extracted C2 with network logs

Workflow 3: Watermark Attribution

[Multiple Beacons] --> [Extract Watermarks] --> [Cluster by Watermark] --> [Attribution]
                                                                               |
                                                                               v
                                                                     [Campaign Correlation]

Steps:

  1. Collection: Gather beacon samples from incident or threat intel feeds
  2. Watermark Extraction: Extract watermark value from each sample
  3. Database Lookup: Check watermark against known databases
  4. Clustering: Group beacons sharing the same watermark
  5. Infrastructure Overlap: Correlate C2 infrastructure across cluster
  6. Attribution Assessment: Link to known threat actor or cracked license

Workflow 4: C2 Traffic Detection

[Beacon Config] --> [Extract C2 Profile] --> [Generate Signatures] --> [Deploy to NIDS]
                                                                            |
                                                                            v
                                                                   [Monitor Network Traffic]

Steps:

  1. Profile Extraction: Parse malleable C2 profile from beacon config
  2. Pattern Identification: Identify unique HTTP headers, URIs, and encoding
  3. Signature Creation: Write Suricata/Snort rules matching C2 patterns
  4. Deployment: Deploy signatures to network detection infrastructure
  5. Validation: Test signatures against captured beacon traffic
  6. Monitoring: Alert on matching network flows for active beacons