{
  "id": "investigation-summary:c9be30de-56b8-4144-a804-f2c124bf9bcc",
  "type": "pcap-investigation-summary",
  "label": "PCAP investigation summary",
  "model": "gpt-4.1-2025-04-14",
  "stale": false,
  "status": "analyst-review-required",
  "content": "# PCAP investigation summary\n\n## What happened\n\nThe host Ferguson-Win-PC at IP 10.2.23.231 downloaded four different PE files from external servers using HTTP requests, with three files served under PNG or JPG extensions, which is inconsistent with their content type and is suspicious.\n\nA PE file named 'troll1.jpg' was also downloaded from 209.141.55.226 by the same host Ferguson-Win-PC at 10.2.23.231, further supporting suspicious transfer activity.\n\n## Who was involved\n\n- Ferguson-Win-PC at 10.2.23.231 is the client responsible for the suspicious file downloads.\n\n## What remains uncertain\n\n- There is no direct evidence that any of the downloaded PE files were executed or that the device was successfully compromised during the capture window.\n\n## Next check\n\n- Perform endpoint forensics on Ferguson-Win-PC to check for execution of the downloaded PE files and signs of follow-on compromise or persistence.\n\nAnalyst-review draft. Exact evidence references and provider provenance are retained in the structured record.",
  "summary": "The host Ferguson-Win-PC at IP 10.2.23.231 downloaded four different PE files from external servers using HTTP requests, with three files served under PNG or JPG extensions, which is inconsistent with their content type and is suspicious. A PE file named 'troll1.jpg' was also downloaded from 209.141.55.226 by the same host Ferguson-Win-PC at 10.2.23.231, further supporting suspicious transfer activity.",
  "coverage": {
    "warnings": [],
    "projection": "pcap-brief-evidence-v2-compact",
    "source_digest": "6a25f7bd75a7b1f270d5c53f627231d7b0295bb014e382846fcd0e77a59bd0c8",
    "candidate_total": 6,
    "omitted_records": {
      "findings": 15,
      "artifacts": 46,
      "candidates": 1,
      "identities": 0,
      "techniques": 1,
      "selected_network_events": 2
    },
    "compact_evidence": true,
    "included_records": {
      "limits": 1,
      "capture": 1,
      "network": 2,
      "findings": 1,
      "transfers": 6,
      "candidates": 5,
      "identities": 6,
      "reputation_coverage": 1
    },
    "supplement_scope": "Bounded selected packet metadata, direct reputation, identities and transfer relationships; no payload bodies, prior-case content or exhaustive inventory. Full data remains in source analysis.",
    "source_characters": 9992,
    "enrichment_retained_targets": 53
  },
  "filename": "2019-02-23-traffic-analysis-exercise.pcap",
  "provider": "openai",
  "report_id": "pcap:5bff54cd-16de-44cb-a009-c88818ce138f",
  "created_at": "2026-09-22T19:14:45.529186+00:00",
  "structured": {
    "iocs": [],
    "ttps": [],
    "identities": [
      {
        "kind": "ip",
        "text": "Ferguson-Win-PC at 10.2.23.231 is the client responsible for the suspicious file downloads.",
        "basis": "observed",
        "value": "10.2.23.231",
        "evidence": [
          {
            "end": 354,
            "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":292,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"},{\"account\":\"\",\"frame_number\":3113,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[\"10.2.23.231\"],\"mac_addresses\":[\"00:11:0a:9f:c0:2d\",\"00:11:0a:9f:c0:2d,00:11:0a:9f:c0:2d\"],\"type\":\"hostname\",\"value\":\"Ferguson-Win-PC\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#identity/identity-e8f170920b9ee1218bc70d24",
            "source_id": "S0019",
            "source_sha256": "3790480dc450bb73c6aaac4eb2da8d3cc7b9a9a2a525afee7737f3d0058ce0d8"
          }
        ]
      }
    ],
    "next_steps": [
      {
        "text": "Perform endpoint forensics on Ferguson-Win-PC to check for execution of the downloaded PE files and signs of follow-on compromise or persistence.",
        "basis": "assessment",
        "evidence": [
          {
            "end": 354,
            "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":292,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"},{\"account\":\"\",\"frame_number\":3113,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[\"10.2.23.231\"],\"mac_addresses\":[\"00:11:0a:9f:c0:2d\",\"00:11:0a:9f:c0:2d,00:11:0a:9f:c0:2d\"],\"type\":\"hostname\",\"value\":\"Ferguson-Win-PC\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#identity/identity-e8f170920b9ee1218bc70d24",
            "source_id": "S0019",
            "source_sha256": "3790480dc450bb73c6aaac4eb2da8d3cc7b9a9a2a525afee7737f3d0058ce0d8"
          }
        ]
      }
    ],
    "uncertainties": [
      {
        "text": "There is no direct evidence that any of the downloaded PE files were executed or that the device was successfully compromised during the capture window.",
        "basis": "assessment",
        "evidence": [
          {
            "end": 400,
            "quote": "{\"internal_lookup\":{\"matched_observables\":0,\"no_exact_match\":207,\"observable_limit\":5000,\"observables_checked\":207,\"observables_total\":207,\"prior_case_limit_reached\":true,\"prior_cases_checked\":50,\"truncated\":false},\"visibility\":\"Encrypted application payloads are not decrypted. No endpoint execution, persistence or actor attribution is established by a download or connection alone.\",\"warnings\":[]}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#coverage",
            "source_id": "S0002",
            "source_sha256": "ae594e11f2916abeb727b9d97c91e2079bd5b88ec578839886bb34c0eb584648"
          }
        ]
      }
    ],
    "what_happened": [
      {
        "text": "The host Ferguson-Win-PC at IP 10.2.23.231 downloaded four different PE files from external servers using HTTP requests, with three files served under PNG or JPG extensions, which is inconsistent with their content type and is suspicious.",
        "basis": "observed",
        "evidence": [
          {
            "end": 365,
            "quote": "{\"client_ip\":\"10.2.23.231\",\"completeness\":\"matches-declared-content-length\",\"content_kind\":\"pe\",\"match_basis\":\"exact-sha256-of-decoded-http-response-body\",\"request_frame\":10966,\"response_frame\":12777,\"server_ip\":\"85.143.218.7\",\"sha256\":\"38c6c5b8d6fa71d9856758a5c0c2ac9d0a0a1450f75bb1004dd988e23d73a312\",\"url_without_query_or_fragment\":\"http://85.143.218.7/win.png\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#artifact/artifact-a44db5d69b9bc8f3fdaaff4e",
            "source_id": "S0009",
            "source_sha256": "dc4bad660a0ebb882b4f85d00cc0cc57e521f56625f723b25bbc996f1d6e8827"
          },
          {
            "end": 365,
            "quote": "{\"client_ip\":\"10.2.23.231\",\"completeness\":\"matches-declared-content-length\",\"content_kind\":\"pe\",\"match_basis\":\"exact-sha256-of-decoded-http-response-body\",\"request_frame\":20146,\"response_frame\":20903,\"server_ip\":\"85.143.218.7\",\"sha256\":\"3abae6dd2ddae23b2de2ccbcc160a4a5773bef8934d0e6896d50197c3d3c417f\",\"url_without_query_or_fragment\":\"http://85.143.218.7/sin.png\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#artifact/artifact-64c04b868e21280de7169f44",
            "source_id": "S0010",
            "source_sha256": "4ea9e37369f96831c09cd37a04ed77616dd06a37f46e19bb2f586781cb98a213"
          },
          {
            "end": 365,
            "quote": "{\"client_ip\":\"10.2.23.231\",\"completeness\":\"matches-declared-content-length\",\"content_kind\":\"pe\",\"match_basis\":\"exact-sha256-of-decoded-http-response-body\",\"request_frame\":11986,\"response_frame\":13356,\"server_ip\":\"85.143.218.7\",\"sha256\":\"4c957072ab097d3474039f432466cd251d1dc7d91559b76d4e5ead4a8bd499d5\",\"url_without_query_or_fragment\":\"http://85.143.218.7/tin.png\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#artifact/artifact-c300c6cc1195496e5d11e6e0",
            "source_id": "S0011",
            "source_sha256": "0088e18d704ffa24c3bc27e633602dd909ab2544352a11393e294e385b3bfef1"
          }
        ]
      },
      {
        "text": "A PE file named 'troll1.jpg' was also downloaded from 209.141.55.226 by the same host Ferguson-Win-PC at 10.2.23.231, further supporting suspicious transfer activity.",
        "basis": "observed",
        "evidence": [
          {
            "end": 370,
            "quote": "{\"client_ip\":\"10.2.23.231\",\"completeness\":\"matches-declared-content-length\",\"content_kind\":\"pe\",\"match_basis\":\"exact-sha256-of-decoded-http-response-body\",\"request_frame\":3119,\"response_frame\":3542,\"server_ip\":\"209.141.55.226\",\"sha256\":\"8cf2cddda8522975a22da3da429339be471234eacc0e11c099d6dcb732cf3cbb\",\"url_without_query_or_fragment\":\"http://209.141.55.226/troll1.jpg\"}",
            "start": 0,
            "reference": "/api/pcap/analyses/5bff54cd-16de-44cb-a009-c88818ce138f#artifact/artifact-162a2189c16314dce4cad0b7",
            "source_id": "S0012",
            "source_sha256": "adf7be9511b7a984bcf0b8b71accfa50a176332b34a275e3a281ac5574b6cbd7"
          }
        ]
      }
    ]
  },
  "validation": "schema-and-exact-quote-binding; not semantic proof",
  "word_count": 116,
  "analysis_id": "5bff54cd-16de-44cb-a009-c88818ce138f",
  "token_usage": {
    "total_tokens": 18165,
    "prompt_tokens": 16628,
    "completion_tokens": 1537
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  "authoritative": false,
  "effective_tlp": "TLP:CLEAR",
  "source_sha256": "8124809c067ef96483d395c70c2ab282b1c60222201454e993ba10960a30d66c",
  "capture_sha256": "f6d740aeaac9e7d23843b481b7cbc179117cd21fab2f0d82c0e94fe8ba092775",
  "prompt_version": "pcap-investigation-summary-v5",
  "requested_model": "gpt-4.1",
  "source_manifest": [
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}