XML signature verification bypass due improper verification of signature / signature spoofing
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.0.0
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- 1 proof of concept on GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: total
Summary
xml-crypto is an xml digital signature and encryption library for Node.js. In affected versions the default configuration does not check authorization of the signer, it only checks the validity of the signature per section 3.2.2 of the w3 xmldsig-core-20080610 spec. As such, without additional validation steps, the default configuration allows a malicious actor to re-sign an XML document, place the certificate in a `<KeyInfo />` element, and pass `xml-crypto` default validation checks. As a result `xml-crypto` trusts by default any certificate provided via digitally signed XML document's `<KeyInfo />`. `xml-crypto` prefers to use any certificate provided via digitally signed XML document's `<KeyInfo />` even if library was configured to use specific certificate (`publicCert`) for signature verification purposes. An attacker can spoof signature verification by modifying XML document and replacing existing signature with signature generated with malicious private key (created by attacker) and by attaching that private key's certificate to `<KeyInfo />` element. This vulnerability is combination of changes introduced to `4.0.0` on pull request 301 / commit `c2b83f98` and has been addressed in version 6.0.0 with pull request 445 / commit `21201723d`. Users are advised to upgrade. Users unable to upgrade may either check the certificate extracted via `getCertFromKeyInfo` against trusted certificates before accepting the results of the validation or set `xml-crypto's getCertFromKeyInfo` to `() => undefined` forcing `xml-crypto` to use an explicitly configured `publicCert` or `privateKey` for signature verification.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: total
- Record last updated
Affected versions
- node-saml xml-crypto
From 4.0.0 · fixed in 6.0.0
- xml-cryptonpm
From 4.0.0 · fixed in 6.0.0