{ "id": "investigation-summary:642e8b54-ddd2-4167-9588-4c9eeb609cf2", "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 10.18.20.97, identified as Juanita-Work-PC, engaged in normal directory service protocol activity using LDAP and DRSUAPI with another internal address \\(10.18.20.8\\); these operations are consistent with standard Windows logon processes and no evidence in the capture supports credential theft, discovery, or DCSync attacks.\n\n## Who was involved\n\n- 10.18.20.97 is the primary observed host in domain directory protocol traffic, associated with accounts JUANITA-WORK-PC$ and momia.juanita, and hostname Juanita-Work-PC.\n- JUANITA-WORK-PC$ is an account used by 10.18.20.97 as a Kerberos client principal.\n- momia.juanita is an account used by 10.18.20.97 as a Kerberos client principal.\n\n## What remains uncertain\n\n- No exfiltration, malware delivery, or evidence of compromise was observed, but coverage is limited to network activity and encrypted payloads were not decrypted.\n\n## Next check\n\n- Review endpoints for execution, persistence, or suspicious process activity not visible in the capture to confirm absence of malicious behavior.\n\nAnalyst-review draft. Exact evidence references and provider provenance are retained in the structured record.", "summary": "The host 10.18.20.97, identified as Juanita-Work-PC, engaged in normal directory service protocol activity using LDAP and DRSUAPI with another internal address (10.18.20.8); these operations are consistent with standard Windows logon processes and no evidence in the capture supports credential theft, discovery, or DCSync attacks.", "coverage": { "warnings": [], "projection": "pcap-brief-evidence-v1", "source_digest": "2ce5685240d4e8d4a57342c7b2fcec99b8925adbdbc1f79c94697f24e9fa6993", "candidate_total": 0, "omitted_records": { "findings": 0, "artifacts": 18, "candidates": 0, "identities": 0, "techniques": 0, "selected_network_events": 0 }, "included_records": { "limits": 1, "capture": 1, "findings": 4, "identities": 3, "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": 3529, "enrichment_retained_targets": 60 }, "filename": "2019-12-03-traffic-analysis-exercise.pcap", "provider": "openai", "report_id": "pcap:fa0da8be-03fb-404d-a526-6c99c6b4f000", "created_at": "2026-09-22T18:59:42.457652+00:00", "structured": { "iocs": [], "ttps": [], "identities": [ { "kind": "ip", "text": "10.18.20.97 is the primary observed host in domain directory protocol traffic, associated with accounts JUANITA-WORK-PC$ and momia.juanita, and hostname Juanita-Work-PC.", "basis": "observed", "value": "10.18.20.97", "evidence": [ { "end": 329, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":32,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":40,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.18.20.97\"],\"mac_addresses\":[\"00:01:24:56:9b:cf\"],\"type\":\"account\",\"value\":\"JUANITA-WORK-PC$\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-6d9e30c8fcee7fb94a00fa9c", "source_id": "S0004", "source_sha256": "bd51323c4b0ae8c0b0899bebe32c1a8aec21c5e0208def4f935f220e6cc07ead" }, { "end": 326, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":89,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":97,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.18.20.97\"],\"mac_addresses\":[\"00:01:24:56:9b:cf\"],\"type\":\"account\",\"value\":\"momia.juanita\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-d523bf030d121b54f401ab44", "source_id": "S0005", "source_sha256": "2d22585e1020e20c5f274b149ef6e08cd112288b194f0ed5894304b1aee9aa04" }, { "end": 228, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":16506,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[],\"mac_addresses\":[\"00:01:24:56:9b:cf,00:01:24:56:9b:cf\"],\"type\":\"hostname\",\"value\":\"Juanita-Work-PC\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-028d078a83f9e45d3ea0abb3", "source_id": "S0006", "source_sha256": "33218ed9ab5c36a71818339a4aa940d36de7bd9fa2113a24393652291e359163" } ] }, { "kind": "account", "text": "JUANITA-WORK-PC$ is an account used by 10.18.20.97 as a Kerberos client principal.", "basis": "observed", "value": "JUANITA-WORK-PC$", "evidence": [ { "end": 329, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":32,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":40,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.18.20.97\"],\"mac_addresses\":[\"00:01:24:56:9b:cf\"],\"type\":\"account\",\"value\":\"JUANITA-WORK-PC$\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-6d9e30c8fcee7fb94a00fa9c", "source_id": "S0004", "source_sha256": "bd51323c4b0ae8c0b0899bebe32c1a8aec21c5e0208def4f935f220e6cc07ead" } ] }, { "kind": "account", "text": "momia.juanita is an account used by 10.18.20.97 as a Kerberos client principal.", "basis": "observed", "value": "momia.juanita", "evidence": [ { "end": 326, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":89,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":97,\"owner_ip\":\"10.18.20.97\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.18.20.97\"],\"mac_addresses\":[\"00:01:24:56:9b:cf\"],\"type\":\"account\",\"value\":\"momia.juanita\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-d523bf030d121b54f401ab44", "source_id": "S0005", "source_sha256": "2d22585e1020e20c5f274b149ef6e08cd112288b194f0ed5894304b1aee9aa04" } ] } ], "next_steps": [ { "text": "Review endpoints for execution, persistence, or suspicious process activity not visible in the capture to confirm absence of malicious behavior.", "basis": "assessment", "evidence": [ { "end": 400, "quote": "{\"internal_lookup\":{\"matched_observables\":0,\"no_exact_match\":565,\"observable_limit\":5000,\"observables_checked\":565,\"observables_total\":565,\"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/fa0da8be-03fb-404d-a526-6c99c6b4f000#coverage", "source_id": "S0002", "source_sha256": "61eb9abcf26d6a70e59f5682dbd716a6c7f15e63e838ee9d6769520495e2c455" } ] } ], "uncertainties": [ { "text": "No exfiltration, malware delivery, or evidence of compromise was observed, but coverage is limited to network activity and encrypted payloads were not decrypted.", "basis": "assessment", "evidence": [ { "end": 400, "quote": "{\"internal_lookup\":{\"matched_observables\":0,\"no_exact_match\":565,\"observable_limit\":5000,\"observables_checked\":565,\"observables_total\":565,\"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/fa0da8be-03fb-404d-a526-6c99c6b4f000#coverage", "source_id": "S0002", "source_sha256": "61eb9abcf26d6a70e59f5682dbd716a6c7f15e63e838ee9d6769520495e2c455" } ] } ], "what_happened": [ { "text": "The host 10.18.20.97, identified as Juanita-Work-PC, engaged in normal directory service protocol activity using LDAP and DRSUAPI with another internal address (10.18.20.8); these operations are consistent with standard Windows logon processes and no evidence in the capture supports credential theft, discovery, or DCSync attacks.", "basis": "assessment", "evidence": [ { "end": 412, "quote": "{\"explanation\":\"Directory protocol operations were decoded. Normal Windows logon uses these protocols; activity alone does not establish discovery, credential theft, or DCSync.\",\"frames\":[4,9,12],\"metrics\":{\"destination\":\"10.18.20.8\",\"event_count\":19,\"operation_numbers\":[\"0\",\"2\",\"3\"],\"protocol\":\"ldap\",\"source\":\"10.18.20.97\"},\"rule_id\":\"directory-service-activity\",\"title\":\"Directory-service protocol activity\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-2d54f222e676c2fef177f646", "source_id": "S0007", "source_sha256": "55827b42eb977179b4d4754f0032c6922e9bb7f680db7dd22ac5b805d84c7a77" }, { "end": 430, "quote": "{\"explanation\":\"Directory protocol operations were decoded. Normal Windows logon uses these protocols; activity alone does not establish discovery, credential theft, or DCSync.\",\"frames\":[6,11,13],\"metrics\":{\"destination\":\"10.18.20.97\",\"event_count\":15,\"operation_numbers\":[\"1\",\"4,19,19,19,5\",\"4,5\",\"5\"],\"protocol\":\"ldap\",\"source\":\"10.18.20.8\"},\"rule_id\":\"directory-service-activity\",\"title\":\"Directory-service protocol activity\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-53ea8ee6b528ae71d4383723", "source_id": "S0008", "source_sha256": "c827fa7c4b078f9ae940973d056ca14ae10aed1858d456af79e61a1817871c71" }, { "end": 420, "quote": "{\"explanation\":\"Directory protocol operations were decoded. Normal Windows logon uses these protocols; activity alone does not establish discovery, credential theft, or DCSync.\",\"frames\":[141,143,145],\"metrics\":{\"destination\":\"10.18.20.8\",\"event_count\":4,\"operation_numbers\":[\"0\",\"1\",\"12\"],\"protocol\":\"drsuapi\",\"source\":\"10.18.20.97\"},\"rule_id\":\"directory-service-activity\",\"title\":\"Directory-service protocol activity\"}", "start": 0, "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-72107aa073ef73382cd79619", "source_id": "S0009", "source_sha256": "dcc5d3399ed3ebb49c6c77a993334ffd43e3d1cca16e0211c9954cb045d34b23" } ] } ] }, "validation": "schema-and-exact-quote-binding; not semantic proof", "word_count": 131, "analysis_id": "fa0da8be-03fb-404d-a526-6c99c6b4f000", "token_usage": { "total_tokens": 4669, "prompt_tokens": 4216, "completion_tokens": 453 }, "authoritative": false, "effective_tlp": "TLP:CLEAR", "source_sha256": "a374f16e427e0a4be1a5f489d46f6e8e87588a412caa2ff11bd21db7d49ade72", "capture_sha256": "01da378585edbbc7d97e9cd91418a50cc506468d615ff0002b7f4bc34e0cbe0a", "prompt_version": "pcap-investigation-summary-v5", "requested_model": "gpt-4.1", "source_manifest": [ { "kind": "packet_fact", "offset": 0, "sha256": "d164b3920600ccd5ba2b9c08d14281f5c36f3ead9ab06dcc00474e4449649438", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#capture", "source_id": "S0001" }, { "kind": "packet_fact", "offset": 0, "sha256": "61eb9abcf26d6a70e59f5682dbd716a6c7f15e63e838ee9d6769520495e2c455", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#coverage", "source_id": "S0002" }, { "kind": "intelligence_lead", "offset": 0, "sha256": "a6dbb4fac9e7ce3f6de989270a5599c382ab54f44f32049dc646899bb8c65831", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#enrichment-coverage", "source_id": "S0003" }, { "kind": "packet_fact", "offset": 0, "sha256": "bd51323c4b0ae8c0b0899bebe32c1a8aec21c5e0208def4f935f220e6cc07ead", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-6d9e30c8fcee7fb94a00fa9c", "source_id": "S0004" }, { "kind": "packet_fact", "offset": 0, "sha256": "2d22585e1020e20c5f274b149ef6e08cd112288b194f0ed5894304b1aee9aa04", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-d523bf030d121b54f401ab44", "source_id": "S0005" }, { "kind": "packet_fact", "offset": 0, "sha256": "33218ed9ab5c36a71818339a4aa940d36de7bd9fa2113a24393652291e359163", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#identity/identity-028d078a83f9e45d3ea0abb3", "source_id": "S0006" }, { "kind": "rule_candidate", "offset": 0, "sha256": "55827b42eb977179b4d4754f0032c6922e9bb7f680db7dd22ac5b805d84c7a77", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-2d54f222e676c2fef177f646", "source_id": "S0007" }, { "kind": "rule_candidate", "offset": 0, "sha256": "c827fa7c4b078f9ae940973d056ca14ae10aed1858d456af79e61a1817871c71", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-53ea8ee6b528ae71d4383723", "source_id": "S0008" }, { "kind": "rule_candidate", "offset": 0, "sha256": "dcc5d3399ed3ebb49c6c77a993334ffd43e3d1cca16e0211c9954cb045d34b23", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-72107aa073ef73382cd79619", "source_id": "S0009" }, { "kind": "rule_candidate", "offset": 0, "sha256": "1747b09cc158f5563870c9250cee11e3af786e6a7c88ee7ce3e3e4950f76f4af", "reference": "/api/pcap/analyses/fa0da8be-03fb-404d-a526-6c99c6b4f000#finding/finding-79b5d68a2d1e473b9f7c5395", "source_id": "S0010" } ], "token_usage_note": "Provider-reported counts when available; never estimated from character length.", "generation_seconds": 4.296, "generation_attempts": [ { "attempt": 1, "validation": "passed", "token_usage": { "total_tokens": 4669, "prompt_tokens": 4216, "completion_tokens": 453, "prompt_tokens_details": { "audio_tokens": 0, "cached_tokens": 1920 }, "completion_tokens_details": { "audio_tokens": 0, "reasoning_tokens": 0, "accepted_prediction_tokens": 0, "rejected_prediction_tokens": 0 } }, "finish_reason": "stop", "provider_returned_model": "gpt-4.1-2025-04-14" } ], "validation_adjustments": [ { "basis": "assessment", "index": 0, "action": "evidence-level-downgrade", "section": "what_happened" } ], "provider_returned_model": "gpt-4.1-2025-04-14" }