Forge Web Credentials: Web Cookies

ID Name
T1606.001 Web Cookies
T1606.002 SAML Tokens

Adversaries may forge web cookies that can be used to gain access to web applications or Internet services. Web applications and services (hosted in cloud SaaS environments or on-premise servers) often use session cookies to authenticate and authorize user access.

Adversaries may generate these cookies in order to gain access to web resources. This differs from Steal Web Session Cookie and other similar behaviors in that the cookies are new and forged by the adversary, rather than stolen or intercepted from legitimate users. Most common web applications have standardized and documented cookie values that can be generated using provided tools or interfaces.[1] The generation of web cookies often requires secret values, such as passwords, Private Keys, or other cryptographic seed values.

Once forged, adversaries may use these web cookies to access resources (Web Session Cookie), which may bypass multi-factor and other authentication protection mechanisms.[2][1][3]

ID: T1606.001
Sub-technique of:  T1606
Platforms: IaaS, Linux, SaaS, Windows, macOS
Contributors: Jack Burns, HubSpot
Version: 1.1
Created: 17 December 2020
Last Modified: 24 October 2025

Procedure Examples

ID Name Description
C0024 SolarWinds Compromise

During the SolarWinds Compromise, APT29 bypassed MFA set on OWA accounts by generating a cookie value from a previously stolen secret key.[2]

Mitigations

ID Mitigation Description
M1047 Audit

Administrators should perform an audit of all access lists and the permissions they have been granted to access web applications and services. This should be done extensively on all resources in order to establish a baseline, followed up on with periodic audits of new or updated resources. Suspicious accounts/credentials should be investigated and removed.

M1054 Software Configuration

Configure browsers/applications to regularly delete persistent web cookies.

Detection Strategy

ID Name Analytic ID Analytic Description
DET0171 Detection Strategy for Forged Web Cookies AN0483

Forged cookies in IaaS environments may appear as authentication attempts that bypass MFA, leveraging AssumeRole or session APIs with cookies that were never legitimately issued. Defenders should correlate cloud logs for cookie-based sessions without prior valid authentication, often followed by resource access from unfamiliar IP addresses.

AN0484

Forged web cookies on Windows endpoints can be detected by monitoring unusual modifications of browser cookie stores (e.g., Chrome SQLite DB, Edge cache) by processes outside of browsers, followed by authentication events to SaaS or IaaS services. Defenders may observe processes writing directly to cookie storage paths or injecting tokens into browser sessions.

AN0485

On Linux, defenders may observe forged cookie activity as unauthorized modifications to browser cookie databases (e.g., ~/.mozilla/firefox/*/cookies.sqlite, ~/.config/chromium/Default/Cookies) or scripted injection of session tokens. Suspicious usage includes curl/wget commands embedding forged cookies in headers, correlated with abnormal session activity in SaaS or IaaS logs.

AN0486

Forged cookies on macOS may show up as abnormal access to Safari/Chrome cookie databases in ~/Library/Cookies, combined with unexpected logon sessions authenticated by those cookies. Unified Logs may show cookie injection events or abnormal access patterns to Keychain when linked to browser authentication flows.

AN0487

Forged cookies in SaaS environments manifest as valid web sessions without matching login activity, MFA enforcement bypass, or cookies reused across multiple devices/IPs. Defenders should look for cookie replay, concurrent sessions from multiple geographies, or session tokens generated by unrecognized apps.

References