{ "id": "investigation-summary:7ae590f3-65a9-43e6-a5a2-2f39852714f3", "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\nDuring the observed period, host 10.0.76.109 requested and received a large executable-formatted transfer \\(declared content type application/x-msdownload, size 584192 bytes\\) from 37.46.135.170; no explicit evidence establishes the intent or execution of this payload.\n\n10.0.76.109 was identified as associated with the workstation Bangkok-8ac2-PC and account bangkok-8ac2-pc$ during the capture.\n\n## Who was involved\n\n- 10.0.76.109 is identified as Bangkok-8ac2-PC \\(host\\) and bangkok-8ac2-pc$ \\(account\\).\n- Bangkok-8ac2-PC hostname seen for 10.0.76.109.\n\n## What remains uncertain\n\n- No evidence confirms whether the transferred file on 10.0.76.109 was executed or if it was malicious.\n\n## Next check\n\n- Verify the presence and execution status of the transferred executable on 10.0.76.109 \\(Bangkok-8ac2-PC\\), and inspect for follow-on behavior or compromise indications.\n\nAnalyst-review draft. Exact evidence references and provider provenance are retained in the structured record.", "summary": "During the observed period, host 10.0.76.109 requested and received a large executable-formatted transfer (declared content type application/x-msdownload, size 584192 bytes) from 37.46.135.170; no explicit evidence establishes the intent or execution of this payload. 10.0.76.109 was identified as associated with the workstation Bangkok-8ac2-PC and account bangkok-8ac2-pc$ during the capture.", "coverage": { "warnings": [], "projection": "pcap-brief-evidence-v1", "source_digest": "a523d37fb652442f09fef8af2215fc4fe4de55bef981e80127078b946b703d19", "candidate_total": 0, "omitted_records": { "findings": 10, "artifacts": 33, "candidates": 0, "identities": 0, "techniques": 0, "selected_network_events": 0 }, "included_records": { "limits": 1, "capture": 1, "findings": 10, "transfers": 1, "identities": 6, "techniques": 1, "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": 9500, "enrichment_retained_targets": 57 }, "filename": "2019-06-22-traffic-analysis-exercise.pcap", "provider": "openai", "report_id": "pcap:8879e360-655c-4073-beb9-68018699a4d4", "created_at": "2026-09-22T19:03:35.228910+00:00", "structured": { "iocs": [], "ttps": [], "identities": [ { "kind": "ip", "text": "10.0.76.109 is identified as Bangkok-8ac2-PC (host) and bangkok-8ac2-pc$ (account).", "basis": "observed", "value": "10.0.76.109", "evidence": [ { "end": 354, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":934,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"},{\"account\":\"\",\"frame_number\":4887,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[\"10.0.76.109\"],\"mac_addresses\":[\"78:2b:cb:d4:a5:fe\",\"78:2b:cb:d4:a5:fe,78:2b:cb:d4:a5:fe\"],\"type\":\"hostname\",\"value\":\"Bangkok-8ac2-PC\"}", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-8c40bbfdca199d9772d479f5", "source_id": "S0010", "source_sha256": "63dcd19fb22aa9b2aeaa24ab46e5fcdfa0f72aca6b3ed9711ff09531bdf95134" }, { "end": 331, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":596,\"owner_ip\":\"10.0.76.109\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":604,\"owner_ip\":\"10.0.76.109\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.0.76.109\"],\"mac_addresses\":[\"78:2b:cb:d4:a5:fe\"],\"type\":\"account\",\"value\":\"bangkok-8ac2-pc$\"}", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-3b4e0e1f69626a2e1a544253", "source_id": "S0008", "source_sha256": "09843cd3a6ad15f771f5f6d7a42785b718e464ed95bd7de52f9c119f15b850e3" } ] }, { "kind": "host", "text": "Bangkok-8ac2-PC hostname seen for 10.0.76.109.", "basis": "observed", "value": "Bangkok-8ac2-PC", "evidence": [ { "end": 354, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":934,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"},{\"account\":\"\",\"frame_number\":4887,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[\"10.0.76.109\"],\"mac_addresses\":[\"78:2b:cb:d4:a5:fe\",\"78:2b:cb:d4:a5:fe,78:2b:cb:d4:a5:fe\"],\"type\":\"hostname\",\"value\":\"Bangkok-8ac2-PC\"}", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-8c40bbfdca199d9772d479f5", "source_id": "S0010", "source_sha256": "63dcd19fb22aa9b2aeaa24ab46e5fcdfa0f72aca6b3ed9711ff09531bdf95134" } ] } ], "next_steps": [ { "text": "Verify the presence and execution status of the transferred executable on 10.0.76.109 (Bangkok-8ac2-PC), and inspect for follow-on behavior or compromise indications.", "basis": "assessment", "evidence": [ { "end": 373, "quote": "{\"explanation\":\"HTTP metadata names a script, archive, or executable. This is a transfer candidate, not proof of file type, execution, or malicious intent; legitimate updates use the same formats.\",\"frames\":[4417,4881],\"metrics\":{\"content_type\":\"application/x-msdownload\",\"declared_body_bytes\":584192,\"destination\":\"10.0.76.109\",\"response_count\":1,\"source\":\"37.46.135.170\",", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" }, { "end": 853, "quote": "\"uri\":\"/?NDk4MTE5&tmCVgJMQbeHjv&znbcjFaUOmZy=vest&aTijcut=blackmail&kBgQawTJSFlOAu=difference&NCThQKrrQh=blackmail&lvQmqFyq=constitution&zCrDVEX=known&wLBVVjhJGAWC=detonator&PLFPhyyqZCa=known&lfJYgkH=perpetual&t4tsdfsg4=YPAVwb_q6p3EaEnRGU0p6B_x2NZgMTqZWcEbk_2lv3ybhGJs11kx_R6GYBxewtUFMT4wMWmKjKHqj58EgwV0sC&nVJnyJYij=vest&eZvTJjAeJ=professional&ISzjHlO=strategy&tAMbBJnq=referred&bwgDFqD=strategy&kdPRkesmuQ=heartfelt&ff5sdfds=xHjQMrbYbRfFFYvfKPzEUKxEMUbWA0GKwYeZhajVF5exFD7Gpbr1F", "start": 373, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" }, { "end": 1015, "quote": "xXspVWdCFWEmvtvdLUHIwuh1UPASwJizY&kxbRJWYrNpZbNlVMzU3NDAz\"},\"rule_id\":\"script-or-executable-transfer\",\"title\":\"Script, archive, or executable transfer candidate\"}", "start": 853, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" } ] } ], "uncertainties": [ { "text": "No evidence confirms whether the transferred file on 10.0.76.109 was executed or if it was malicious.", "basis": "assessment", "evidence": [ { "end": 373, "quote": "{\"explanation\":\"HTTP metadata names a script, archive, or executable. This is a transfer candidate, not proof of file type, execution, or malicious intent; legitimate updates use the same formats.\",\"frames\":[4417,4881],\"metrics\":{\"content_type\":\"application/x-msdownload\",\"declared_body_bytes\":584192,\"destination\":\"10.0.76.109\",\"response_count\":1,\"source\":\"37.46.135.170\",", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" } ] } ], "what_happened": [ { "text": "During the observed period, host 10.0.76.109 requested and received a large executable-formatted transfer (declared content type application/x-msdownload, size 584192 bytes) from 37.46.135.170; no explicit evidence establishes the intent or execution of this payload.", "basis": "assessment", "evidence": [ { "end": 373, "quote": "{\"explanation\":\"HTTP metadata names a script, archive, or executable. This is a transfer candidate, not proof of file type, execution, or malicious intent; legitimate updates use the same formats.\",\"frames\":[4417,4881],\"metrics\":{\"content_type\":\"application/x-msdownload\",\"declared_body_bytes\":584192,\"destination\":\"10.0.76.109\",\"response_count\":1,\"source\":\"37.46.135.170\",", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" }, { "end": 853, "quote": "\"uri\":\"/?NDk4MTE5&tmCVgJMQbeHjv&znbcjFaUOmZy=vest&aTijcut=blackmail&kBgQawTJSFlOAu=difference&NCThQKrrQh=blackmail&lvQmqFyq=constitution&zCrDVEX=known&wLBVVjhJGAWC=detonator&PLFPhyyqZCa=known&lfJYgkH=perpetual&t4tsdfsg4=YPAVwb_q6p3EaEnRGU0p6B_x2NZgMTqZWcEbk_2lv3ybhGJs11kx_R6GYBxewtUFMT4wMWmKjKHqj58EgwV0sC&nVJnyJYij=vest&eZvTJjAeJ=professional&ISzjHlO=strategy&tAMbBJnq=referred&bwgDFqD=strategy&kdPRkesmuQ=heartfelt&ff5sdfds=xHjQMrbYbRfFFYvfKPzEUKxEMUbWA0GKwYeZhajVF5exFD7Gpbr1F", "start": 373, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" }, { "end": 1015, "quote": "xXspVWdCFWEmvtvdLUHIwuh1UPASwJizY&kxbRJWYrNpZbNlVMzU3NDAz\"},\"rule_id\":\"script-or-executable-transfer\",\"title\":\"Script, archive, or executable transfer candidate\"}", "start": 853, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019", "source_sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9" } ] }, { "text": "10.0.76.109 was identified as associated with the workstation Bangkok-8ac2-PC and account bangkok-8ac2-pc$ during the capture.", "basis": "observed", "evidence": [ { "end": 354, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":934,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"},{\"account\":\"\",\"frame_number\":4887,\"owner_ip\":\"0.0.0.0\",\"relationship\":\"dhcp-client-assertion\"}],\"ip_addresses\":[\"10.0.76.109\"],\"mac_addresses\":[\"78:2b:cb:d4:a5:fe\",\"78:2b:cb:d4:a5:fe,78:2b:cb:d4:a5:fe\"],\"type\":\"hostname\",\"value\":\"Bangkok-8ac2-PC\"}", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-8c40bbfdca199d9772d479f5", "source_id": "S0010", "source_sha256": "63dcd19fb22aa9b2aeaa24ab46e5fcdfa0f72aca6b3ed9711ff09531bdf95134" }, { "end": 331, "quote": "{\"bindings\":[{\"account\":\"\",\"frame_number\":596,\"owner_ip\":\"10.0.76.109\",\"relationship\":\"kerberos-client-principal\"},{\"account\":\"\",\"frame_number\":604,\"owner_ip\":\"10.0.76.109\",\"relationship\":\"kerberos-client-principal\"}],\"ip_addresses\":[\"10.0.76.109\"],\"mac_addresses\":[\"78:2b:cb:d4:a5:fe\"],\"type\":\"account\",\"value\":\"bangkok-8ac2-pc$\"}", "start": 0, "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-3b4e0e1f69626a2e1a544253", "source_id": "S0008", "source_sha256": "09843cd3a6ad15f771f5f6d7a42785b718e464ed95bd7de52f9c119f15b850e3" } ] } ] }, "validation": "schema-and-exact-quote-binding; not semantic proof", "word_count": 99, "analysis_id": "8879e360-655c-4073-beb9-68018699a4d4", "token_usage": { "total_tokens": 7926, "prompt_tokens": 7379, "completion_tokens": 547 }, "authoritative": false, "effective_tlp": "TLP:CLEAR", "source_sha256": "b9f1a88f1eb5dc39a70c7866539846763b38f3831e54ee0cdd99ef746bfcbc52", "capture_sha256": "6a89013b9e9bc6d443810245b92f49db4df33c1671a43db03a6bbde8f2bc6e63", "prompt_version": "pcap-investigation-summary-v5", "requested_model": "gpt-4.1", "source_manifest": [ { "kind": "packet_fact", "offset": 0, "sha256": "6439c547a5e5a21f38163a97833260c2690b3ca2c738ad6777670adb82697f2c", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#capture", "source_id": "S0001" }, { "kind": "packet_fact", "offset": 0, "sha256": "223a223f07cf978cd974619bb38700140516aa272f609db9920cc4c504655d82", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#coverage", "source_id": "S0002" }, { "kind": "intelligence_lead", "offset": 0, "sha256": "9de0f2b7f9505806be99733037b256e7c790bcd3c7b7ee23a3e310a9d7e91c85", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#enrichment-coverage", "source_id": "S0003" }, { "kind": "packet_fact", "offset": 0, "sha256": "dad6cbeb7da59393bd1426286a1a87e5e4efc122d07841a8ccfc8bd9ae89bff4", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#artifact/artifact-bfa836b5989940b9b854f34a", "source_id": "S0004" }, { "kind": "packet_fact", "offset": 0, "sha256": "457344c847f9a55ecd973bb1058dc663a664dc68110f06dbba1b45e3bc185053", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-c756b40bf52b1ffeb5965832", "source_id": "S0005" }, { "kind": "packet_fact", "offset": 0, "sha256": "d56bb56cd60ccfec895c37741a05312132580ba84ebd2355b9ade7b972e5e73d", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-399638787d1f99cbcf80727c", "source_id": "S0006" }, { "kind": "packet_fact", "offset": 0, "sha256": "4889239cd045fd049a2e103f9a552930eae20a4714d38f4680f242f17f77d666", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-3628d47980bcdb97bfc5c6f9", "source_id": "S0007" }, { "kind": "packet_fact", "offset": 0, "sha256": "09843cd3a6ad15f771f5f6d7a42785b718e464ed95bd7de52f9c119f15b850e3", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-3b4e0e1f69626a2e1a544253", "source_id": "S0008" }, { "kind": "packet_fact", "offset": 0, "sha256": "d710b72d8d33f8fdd4833910c00faf9716ea16c08e511731ebabe0d738484d46", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-46bdca4babd07929ae2ad400", "source_id": "S0009" }, { "kind": "packet_fact", "offset": 0, "sha256": "63dcd19fb22aa9b2aeaa24ab46e5fcdfa0f72aca6b3ed9711ff09531bdf95134", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#identity/identity-8c40bbfdca199d9772d479f5", "source_id": "S0010" }, { "kind": "rule_candidate", "offset": 0, "sha256": "65568cdd4e9e309f6596ba370eb0b54dddd4f81445668b3f9d550242a85c31ab", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-088d67a4a95db14e15918503", "source_id": "S0011" }, { "kind": "rule_candidate", "offset": 0, "sha256": "5546af586b9a0b11c5c9988ddacbc72453a61774e693bac043def78c7d333024", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-11e10d956e266bb1f17197e1", "source_id": "S0012" }, { "kind": "rule_candidate", "offset": 0, "sha256": "24ec6c9cb391682df110b2ba4b505beac5f643904d2c5378b2d682285c910bed", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-18be0b885eee3250f00e4be1", "source_id": "S0013" }, { "kind": "rule_candidate", "offset": 0, "sha256": "64f52c983ed08282e542edbdac3f0ce30b910f48c989c62593337267b04fefb0", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-1ad8745f112f35735cb5a0a8", "source_id": "S0014" }, { "kind": "rule_candidate", "offset": 0, "sha256": "74aba775660e2d302705e6613c23e6ac81098f5460c69bfe33c2c4a0109d00ef", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-1f68a6d774afd56eb1ed1c35", "source_id": "S0015" }, { "kind": "rule_candidate", "offset": 0, "sha256": "9e3df05022bbd62ae9bac3900c4aea06897b55a080c12f4205009eabf2657f9a", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-1fd15c185fe156513055bdf4", "source_id": "S0016" }, { "kind": "rule_candidate", "offset": 0, "sha256": "6defc336f89e897f6f5429c707f5086b24062ff848d915f295b3ab448edcb98e", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-283b7ef7685272ce8421105a", "source_id": "S0017" }, { "kind": "rule_candidate", "offset": 0, "sha256": "e41cd6d4b7369fa0778e4b3a02a88825c560168884831caf3142b184147a38c2", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-2f5b08bb1d3c8868430f4e23", "source_id": "S0018" }, { "kind": "rule_candidate", "offset": 0, "sha256": "e33eda7392e67613de887d5c5707bf0296200dc0784040169aaad759283cb1e9", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-4a116bcfdf925e0d8bfc2ee2", "source_id": "S0019" }, { "kind": "rule_candidate", "offset": 0, "sha256": "93c0ca0f39ac8994c0834d3986c5988a2e456cef246b334b61e39ff1f12058ab", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#finding/finding-5104a0204f7bd3cc9acfeb99", "source_id": "S0020" }, { "kind": "rule_candidate", "offset": 0, "sha256": "d8b659ba0dce903880ef4c61d99bc4ed9ff001196504c13c87ea466cb5de41ce", "reference": "/api/pcap/analyses/8879e360-655c-4073-beb9-68018699a4d4#technique/T1105", "source_id": "S0021" } ], "token_usage_note": "Provider-reported counts when available; never estimated from character length.", "generation_seconds": 5.155, "generation_attempts": [ { "attempt": 1, "validation": "passed", "token_usage": { "total_tokens": 7926, "prompt_tokens": 7379, "completion_tokens": 547, "prompt_tokens_details": { "audio_tokens": 0, "cached_tokens": 0 }, "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" }, { "basis": "assessment", "index": 0, "action": "evidence-level-downgrade", "section": "uncertainties" }, { "index": 0, "action": "optional-claim-omitted", "reason": "identifier_binding", "section": "ttps" } ], "provider_returned_model": "gpt-4.1-2025-04-14" }