CVE-2024-54143

published 2024-12-06

CVE-2024-54143: 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…

Priority P2 63 critical 9.3 CVSS 4.0

AV N AC L AT N PR N UI N VC H VI H VA H SC N SI N SA N E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU X R X V X RE X U X

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.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
openwrt	asu	< 920c8a1	920c8a1

Detection & IOCs extracted from sources · hover to see the quote

• → Detect command injection via package names passed to the 'make' command in the ASU server build process — monitor for shell metacharacters or unexpected subcommands in package name fields submitted to the sysupgrade service ↗
• → Monitor ASU cache key collisions: the service uses a 12-character truncated SHA-256 hash (48-bit entropy) for build artifact caching — alert on cache hits for requests whose package lists or build parameters differ from the originally cached build ↗
• → Audit sysupgrade.openwrt.org (or self-hosted ASU instances) build logs for anomalous package name values containing shell special characters, which could indicate attempted command injection into the build pipeline ↗
• → Flag use of GPU-accelerated hash collision tooling (e.g., Hashcat) targeting 48-bit truncated SHA-256 values in threat-hunting contexts related to OpenWrt ASU infrastructure ↗

• · The patch commit 920c8a1 addresses both the hash truncation and command injection issues — unpatched ASU instances remain vulnerable; self-hosted operators must update immediately ↗
• · Build log visibility is limited to 7 days due to automatic cleanup, so compromise of images older than 7 days prior to December 4, 2024 cannot be ruled out ↗
• · No evidence of exploitation was found in available logs, but the vulnerability has existed for an indeterminate period with no cut-off date ↗

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CWE-328