OpenWrt asu Firmware Image weak hash

Summaryinfo

A vulnerability classified as very critical has been found in OpenWrt asu. Affected is an unknown function of the component Firmware Image Handler. This manipulation causes weak hash. The identification of this vulnerability is CVE-2024-54143. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability classified as very critical was found in OpenWrt asu (version now known). Affected by this vulnerability is some unknown processing of the component Firmware Image Handler. The manipulation with an unknown input leads to a weak hash vulnerability. The CWE definition for the vulnerability is CWE-328. The product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

openwrt/asu is an image on demand server for OpenWrt based distributions. The request hashing mechanism truncates SHA-256 hashes to only 12 characters. This significantly reduces entropy, making it feasible for an attacker to generate collisions. By exploiting this, a previously built malicious image can be served in place of a legitimate one, allowing the attacker to "poison" the artifact cache and deliver compromised images to unsuspecting users. This can be combined with other attacks, such as a command injection in Imagebuilder that allows malicious users to inject arbitrary commands into the build process, resulting in the production of malicious firmware images signed with the legitimate build key. This has been patched with 920c8a1.

The advisory is shared at github.com. This vulnerability is known as CVE-2024-54143 since 11/29/2024. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 12/06/2024). MITRE ATT&CK project uses the attack technique T1600.001 for this issue.

Applying the patch 920c8a1 is able to eliminate this problem.

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

Productinfo

Vendor

• OpenWrt

Name

• asu

Website

• Product: https://github.com/openwrt/asu/

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

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