Web Session Cookie
Sub-technique of AML.T0091 Use Alternate Authentication Material
Description
Adversaries may use stolen web session cookies to authenticate to AI-enabled applications and supporting services as another user. This technique may bypass some multi-factor authentication controls because the session represented by the cookie has already been authenticated.
Authentication cookies are commonly used by web applications and cloud-based services after a user has authenticated, allowing the user to continue using the service without repeatedly passing credentials. These cookies may remain valid for extended periods of time. After obtaining a cookie through Steal Web Session Cookie, an adversary may import the cookie into a browser or automated client they control and access the corresponding application as the victim while the session remains active.
In attacks on AI systems, web session cookies may grant access to AI chat histories, AI agent control panels, model provider dashboards, customer support systems, retrieval or knowledge management interfaces, or AI DevOps resources. If the stolen cookie belongs to an operator, support agent, developer, or administrator, the adversary may be able to view sensitive conversations, manipulate agent configuration, access private data available through AI tools, or perform actions with the victim account's permissions.
- ATLAS ID
- AML.T0091.001
- Maturity
- DemonstratedShown to work in research or red-team exercises.
- Platforms
- Predictive AI
Mitigations
ATLAS 2026.09 lists no mitigation for this technique; see the parent technique.
Case studies that use it
Related ATT&CK technique
ATLAS adapts this technique from MITRE ATT&CK Enterprise.
Across MITRE's defensive frameworks
Linked through the 1 ATT&CK technique above.
Counter with D3FEND
Defensive techniques MITRE D3FEND maps to the same ATT&CK techniques.
- D3-TBAToken-based Authentication1 shared
- D3-TBToken Binding1 shared
- D3-WSAMWeb Session Access Mediation1 shared
- D3-ABPIApplication-based Process Isolation1 shared
- D3-HRHost Reboot1 shared
- D3-HSHost Shutdown1 shared
- D3-KBPIKernel-based Process Isolation1 shared
- D3-PLAProcess Lineage Analysis1 shared
- D3-PSMDProcess Self-Modification Detection1 shared
- D3-PSProcess Suspension1 shared
- D3-PTProcess Termination1 shared
- D3-ANCIAuthentication Cache Invalidation1 shared
Detect with CAR
MITRE CAR analytics that cover the same ATT&CK techniques.