7.5

CVSS Score

3.1

Basic Information

CVE ID

CVE-2023-49087

GHSA ID

GHSA-ww7x-3gxh-qm6r

EPSS Score

0.42985%

CWE

CWE-345

Published

11/28/2023

Updated

12/6/2023

KEV Status

Technology

PHP

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CVE-2023-49087

CVE-2023-49087: Validation of SignedInfo

Validation of an XML Signature requires verification that the hash value of the related XML-document (after any optional transformations and/or normalizations) matches a specific DigestValue-value, but also that the cryptografic signature on the SignedInfo-tree (the one that contains the DigestValue) verifies and matches a trusted public key.

Within the simpleSAMLphp/xml-security library (https://github.com/simplesamlphp/xml-security), the hash is being validated using SignedElementTrait::validateReference, and the signature is being verified in SignedElementTrait::verifyInternal

https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php:

afbeelding

What stands out is that the signature is being calculated over the canonical version of the SignedInfo-tree. The validateReference method, however, uses the original non-canonicalized version of SignedInfo.

Impact

If an attacker somehow (i.e. by exploiting a bug in PHP's canonicalization function) manages to manipulate the canonicalized version's DigestValue, it would be potentially be possible to forge the signature. No possibilities to exploit this were found during the investigation.

(GitHub Advisory)

7.5

CVSS Score

3.1

Basic Information

CVE ID

CVE-2023-49087

GHSA ID

GHSA-ww7x-3gxh-qm6r

EPSS Score

0.42985%

CWE

CWE-345

Published

11/28/2023

Updated

12/6/2023

KEV Status

Technology

PHP

Technical Details

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
simplesamlphp/xml-security	composer	= 1.6.11	1.6.12
simplesamlphp/saml2	composer	= 5.0.0-alpha.12	5.0.0-alpha.13

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stems from the fact that validateReference() was called without being passed the canonicalized SignedInfo. Pre-patch, it directly retrieved SignedInfo from $this->signature (original DOM), while the signature verification used $signedInfo->canonicalize(). This created a discrepancy between the data used for hash validation (original) and cryptographic signature verification (canonicalized). The commit fixes this by constructing a new SignedInfo from the canonicalized data before passing it to validateReference, ensuring both validations operate on the same canonicalized content.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

V*li**tion o* *n XML Si*n*tur* r*quir*s v*ri*i**tion t**t t** **s* v*lu* o* t** r*l*t** XML-*o*um*nt (**t*r *ny option*l tr*ns*orm*tions *n*/or norm*liz*tions) m*t***s * sp**i*i* *i**stV*lu*-v*lu*, *ut *lso t**t t** *rypto*r**i* si*n*tur* on t** Si*n

Reasoning

T** vuln*r**ility st*ms *rom t** ***t t**t `v*li**t*R***r*n**()` w*s **ll** wit*out **in* p*ss** t** **noni**liz** Si*n**In*o. Pr*-p*t**, it *ir**tly r*tri*v** Si*n**In*o *rom `$t*is->si*n*tur*` (ori*in*l *OM), w*il* t** si*n*tur* v*ri*i**tion us** `

7.5

Basic Information

Concerned about an active attack path?

CVE-2023-49087: Validation of SignedInfo

Impact

7.5

Basic Information

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability Intelligence
Miggo AI