TTPwire Vol. 1 · MITRE ATT&CK·Tagged

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PortSwigger Research

The Fragile Lock: Novel Bypasses For SAML Authentication

2025-12-10 · Read original ↗

ATT&CK techniques detected

8 predictions
T1606.002SAML Tokens
88%
"’ s website. since the user is not yet authenticated, the service provider generates a saml authentication request and redirects the user to the identity provider ( idp ) for verification. the idp receives this request, verifies its validity, and then issues a saml response conta…"
T1606.002SAML Tokens
78%
"exploit, and other php xmldsig implementations, such as rob richards ’ xmlseclibs are also affected. in contrast, the xmlsec library and shibboleth xmlsectool are not vulnerable. an example of such a " golden saml response " ( a message that always passes signature validation, re…"
T1606.002SAML Tokens
70%
"enveloped signature inserted into extension point - reserved xml attribute namespace declaration hides signature element from saml processing module but keep it for digital signature - fake signature node remains at assertion element but keep digest value of empty string - finall…"
T1606.002SAML Tokens
62%
"use case scenario - tools - defense - timeline - conclusion security assertion markup language ( saml 2. 0 ) is a complex authentication standard built on insecure and outdated xml technology. these legacy foundations have made the protocol notoriously difficult to maintain and h…"
T1606.002SAML Tokens
60%
"same document. when the service provider processes the response, the signature verification module correctly validates the legitimate portion of the message, while the saml processing logic mistakenly consumes the attacker ’ s injected assertion. as a result, the attacker ’ s for…"
T1606.002SAML Tokens
35%
"support center - published : wednesday, 10 december 2025 at 12 : 32 utc - updated : wednesday, 21 january 2026 at 10 : 34 utc this post shows how to achieve a full authentication bypass in the ruby and php saml ecosystem by exploiting several parser - level inconsistencies : incl…"
T1606.002SAML Tokens
33%
"still relied on two separate xml parsers - rexml and nokogiri - for different parts of the validation process. according to the saml specification, the assertion element - or one of its ancestor elements - must be referenced by the signature element, using an enveloped xml signat…"
T1606.002SAML Tokens
32%
"as defined in the saml core 2. 0 specification : if a saml responder deems a request to be invalid according to saml syntax or processing rules, then if it responds, it must return a saml response message this means that even when a request is malformed or syntactically invalid, …"

Summary

TLDR This post shows how to achieve a full authentication bypass in the Ruby and PHP SAML ecosystem by exploiting several parser-level inconsistencies: including attribute pollution, namespace confusi