PyJWT up to 1.5.0 PEM Encoded Public Key symmetric/asymmetric invalid_strings privileges management

Summaryinfo

A vulnerability was found in PyJWT up to 1.5.0. It has been rated as critical. Impacted is the function invalid_strings of the file symmetric/asymmetric of the component PEM Encoded Public Key Handler. This manipulation causes privileges management. This vulnerability is registered as CVE-2017-12880. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in PyJWT up to 1.5.0 and classified as critical. Affected by this vulnerability is the function invalid_strings of the file symmetric/asymmetric of the component PEM Encoded Public Key Handler. The manipulation with an unknown input leads to a privileges management vulnerability. The CWE definition for the vulnerability is CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In PyJWT 1.5.0 and below the 'invalid_strings' check in 'HMACAlgorithm.prepare_key' does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string '-----BEGIN RSA PUBLIC KEY-----' which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.

The weakness was published 08/16/2017 (GitHub Repository). The advisory is shared at github.com. This vulnerability is known as CVE-2017-12880 since 08/16/2017. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 105453 (openSUSE Security Update : python-PyJWT (openSUSE-2017-1408)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 170461 (OpenSUSE Security Update for python3-PyJWT (openSUSE-SU-2017:2820-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 5 months after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (105453). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• PyJWT

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5.0

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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