SAML Tokens
Where this stands
A reviewer read the telemetry and concluded there is nothing here to detect that a sibling technique does not already cover.
Both analytics describe a correlation over an absence, which is the one shape this corpus's Sigma subset cannot express. AN0418 asks defenders to match a SAML assertion against *missing* Event IDs 4769/1200/1202, or to compare token lifetime, issuer and claims against a baseline -- there is no aggregation, no timeframe and no way to assert that an event did not occur, and both mutable knobs (TokenLifetimeThreshold, TrustedIssuerList) are threshold/baseline comparisons rather than field matches. The absence is also the whole point of the technique: a Golden SAML token forged offline with a stolen token-signing certificate never touches the AD FS server, so even where AD FS auditing writes 1200 (token issued) and 1202 (credential validated) into the Security log, the forged token produces no such record at all, and a rule that selects on 1200/1202 fires only on legitimate issuance. […]
What the technique is
An adversary may forge SAML tokens with any permissions claims and lifetimes if they possess a valid SAML token-signing certificate. The default lifetime of a SAML token is one hour, but the validity period can be specified in the NotOnOrAfter value of the conditions... element in a token. This value can be changed using the AccessTokenLifetime in a LifetimeTokenPolicy. Forged SAML tokens enable adversaries to authenticate across services that use SAML 2.0 as an SSO (single sign-on) mechanism. An adversary may utilize Private Keys to compromise an organization's token-signing certificate to create forged SAML tokens. If the adversary has sufficient permissions to establish a new federation trust with their own Active Directory Federation Services (AD FS) server, they may instead generate their own trusted token-signing certificate. This differs from Steal Application Access Token and other similar behaviors in that the tokens are new and forged by the adversary, rather than stolen or intercepted from legitimate users. An adversary may gain administrative Entra ID privileges if a SAML token is forged which claims to represent a highly privileged account. This may lead to Use Alternate Authentication Material, which may bypass multi-factor and other authentication protection mechanisms.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0418
Forged SAML tokens can be observed as authentication attempts with valid signatures but missing expected preceding Kerberos or authentication events. Defenders may correlate SAML assertions with absent Event IDs 4769, 1200, or 1202, or tokens issued with abnormal lifetimes, issuers, or claims compared to baseline.
- AN0419
Forged SAML tokens in IaaS environments often manifest as cross-cloud or cross-account authentication without matching STS events. Defenders may see AssumeRole or GetFederationToken API usage without a corresponding SAML assertion log from the trusted IdP.
- AN0420
Forged SAML tokens may be used on Windows systems to authenticate to federated apps without normal Kerberos activity. Defenders may detect anomalous event correlation, where access to SaaS/O365 via SAML occurs without prior TGT requests or user logons.
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