Malicious code was discovered in the upstream tarballs of xz, starting with version 5.6.0. Through a series of complex obfuscations, the liblzma build process extracts a prebuilt object file from a disguised test file existing in the source code, which is then used to modify specific functions in the liblzma code. This results in a modified liblzma library that can be used by any software linked against this library, intercepting and modifying the data interaction with this library.
This alert has come from: https://www.moxa.com/en/support/product-support/security-advisory/mpsa-243094-moxa’s-response-regarding-xz-containing-malware-backdoor-(cve-2024-3094)