{
 "public_id": "AIR-2025-0165",
 "incident_id": "2025-11-microsoft-sesameop",
 "date_disclosed": "2025-11-03",
 "date_occurred": "2025-07-01",
 "title": "SesameOp: backdoor abusing the OpenAI Assistants API as a covert command-and-control channel",
 "class": "in_the_wild",
 "attack_surface": "agent_framework",
 "initial_vector": "compromised_host_web_shells",
 "agent_capability_abused": [
  "assistants_api_relay",
  "command_fetch_and_execute",
  "assistants_api_vector_stores",
  "model_provider_as_c2_transport"
 ],
 "target_product": "OpenAI Assistants API (abused as C2)",
 "target_vendor": "OpenAI",
 "autonomy_level": "fully_autonomous",
 "impact_realized": true,
 "impact_type": [
  "espionage",
  "persistence",
  "data_exfiltration",
  "command_and_control"
 ],
 "blast_radius": "one compromised enterprise environment (months of dwell time)",
 "cve": [],
 "taxonomy": {
  "owasp_asi": [
   "ASI04",
   "ASI02"
  ],
  "mitre_atlas": [
   "AML.CS0042"
  ],
  "labels": [
   "ai_api_as_c2",
   "living_off_trusted_services",
   "espionage"
  ]
 },
 "defense_present": "network egress monitoring",
 "defense_bypassed": true,
 "fix_shipped": "OpenAI disabled the abused account/API key; Microsoft published detections",
 "primary_sources": [
  "https://www.microsoft.com/en-us/security/blog/2025/11/03/sesameop-novel-backdoor-uses-openai-assistants-api-for-command-and-control/",
  "https://raw.githubusercontent.com/mitre-atlas/atlas-data/main/dist/v6/ATLAS-2026.07.yaml"
 ],
 "verified_quote": "a component of the backdoor uses the OpenAI Assistants API as a storage or relay mechanism to fetch commands, which the malware then runs.",
 "confidence": "high",
 "notes": "Microsoft DART. Borderline for an agent corpus: the AI service is abused as infrastructure rather than being the acting agent, but it is a real in-the-wild compromise turning on agent-API semantics. | Merged from duplicate id `2025-07-sesameop-openai-assistants-c2`. Also reported as: 'SesameOp: espionage backdoor using the OpenAI Assistants API as its command-and-control channel'.",
 "risk_category": "security_fraud",
 "risk_secondary": [
  "privacy"
 ],
 "risk_subcategory": "Supply Chain Compromise",
 "risk_sub_secondary": [
  "Persistence & Covert C2"
 ],
 "ai_entity": "generative",
 "agency": "ai_as_target",
 "agency_debatable": true,
 "agency_reason": "the Assistants API is abused as C2 transport, not attacked and not acting",
 "vector_family": "other",
 "vector_detail": "compromised_host_web_shells",
 "guardrail_kind": [
  "human_supervision",
  "permission_scope"
 ],
 "guardrail_outcome": "silent",
 "xrefs": {
  "aiid": [],
  "atlas": [
   "AML.CS0042"
  ],
  "cve": [],
  "ghsa": []
 },
 "primary_asi": "ASI04",
 "agent_framework": "openai_agents_sdk",
 "model_provider": "openai",
 "model_name": "",
 "detection_mechanism": "vendor_disclosure",
 "tool_access": "unknown",
 "financial_loss_band": "unknown",
 "eai_category": "supply_chain_vulnerabilities",
 "eai_domain": "tool_misuse",
 "eai_secondary": [
  "privilege_escalation",
  "data_exfiltration_channels"
 ],
 "eai_reason": "subcategory: Supply Chain Compromise",
 "asi_curated": [],
 "asi_scope": "in_scope",
 "asi_provenance": "rule",
 "asi_reason": "ASI04 (eai_category=supply_chain_vulnerabilities); ASI02 (impact=tool_misuse)",
 "submitted_by": "EAI Internal"
}