CVE-2020-5390 - Improper Verification of Cryptographic Signature

Severity

75%

Complexity

39%

Confidentiality

60%

PySAML2 before 5.0.0 does not check that the signature in a SAML document is enveloped and thus signature wrapping is effective, i.e., it is affected by XML Signature Wrapping (XSW). The signature information and the node/object that is signed can be in different places and thus the signature verification will succeed, but the wrong data will be used. This specifically affects the verification of assertion that have been signed.

PySAML2 before 5.0.0 does not check that the signature in a SAML document is enveloped and thus signature wrapping is effective, i.e., it is affected by XML Signature Wrapping (XSW). The signature information and the node/object that is signed can be in different places and thus the signature verification will succeed, but the wrong data will be used. This specifically affects the verification of assertion that have been signed.

CVSS 3.1 Base Score 7.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

CVSS 2.0 Base Score 5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:P/A:N).

Demo Examples

Improper Verification of Cryptographic Signature

CWE-347

In the following code, a JarFile object is created from a downloaded file.


               
JarFile jf = new JarFile(f);

The JAR file that was potentially downloaded from an untrusted source is created without verifying the signature (if present). An alternate constructor that accepts a boolean verify parameter should be used instead.

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