randombit botan up to 2.19.3 X.509 Certificate amplification

Summaryinfo

A vulnerability classified as critical was found in randombit botan up to 2.19.3. This issue affects some unknown processing of the component X.509 Certificate Handler. Such manipulation leads to amplification. This vulnerability is uniquely identified as CVE-2024-34703. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in randombit botan up to 2.19.3 and classified as critical. Affected by this issue is an unknown function of the component X.509 Certificate Handler. The manipulation with an unknown input leads to a amplification vulnerability. Using CWE to declare the problem leads to CWE-405. The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric." Impacted is availability. CVE summarizes:

Botan is a C++ cryptography library. X.509 certificates can identify elliptic curves using either an object identifier or using explicit encoding of the parameters. Prior to versions 3.3.0 and 2.19.4, an attacker could present an ECDSA X.509 certificate using explicit encoding where the parameters are very large. The proof of concept used a 16Kbit prime for this purpose. When parsing, the parameter is checked to be prime, causing excessive computation. This was patched in 2.19.4 and 3.3.0 to allow the prime parameter of the elliptic curve to be at most 521 bits. No known workarounds are available. Note that support for explicit encoding of elliptic curve parameters is deprecated in Botan.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2024-34703 since 05/07/2024. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 240496 (Ubuntu 22.04 LTS / 24.04 LTS / 24.10 : Botan vulnerabilities (USN-7586-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.19.4 or 3.3.0 eliminates this vulnerability. Applying the patch 08c404b23740babee1f6aa51b54e966029aadee4 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (240496) and EUVD (EUVD-2024-34998). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• randombit

Name

• botan

Version

• 2.19.0
• 2.19.1
• 2.19.2
• 2.19.3

License

• open-source

Website

• Product: https://github.com/randombit/botan/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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