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.
{ "availability": "No subscription required", "ubuntu_priority": "critical", "binaries": [ { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "liblzma-dev" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "liblzma-doc" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "liblzma5" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "liblzma5-dbgsym" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "xz-utils" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "xz-utils-dbgsym" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "xzdec" }, { "binary_version": "5.2.4-1ubuntu1.1", "binary_name": "xzdec-dbgsym" } ], "priority_reason": "Results in a backdoor in sshd" }
{ "availability": "No subscription required", "ubuntu_priority": "critical", "binaries": [ { "binary_version": "5.2.5-2ubuntu1", "binary_name": "liblzma-dev" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "liblzma-doc" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "liblzma5" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "liblzma5-dbgsym" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "xz-utils" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "xz-utils-dbgsym" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "xzdec" }, { "binary_version": "5.2.5-2ubuntu1", "binary_name": "xzdec-dbgsym" } ], "priority_reason": "Results in a backdoor in sshd" }
{ "availability": "No subscription required", "ubuntu_priority": "critical", "binaries": [ { "binary_version": "5.4.5-0.3", "binary_name": "liblzma-dev" }, { "binary_version": "5.4.5-0.3", "binary_name": "liblzma-doc" }, { "binary_version": "5.4.5-0.3", "binary_name": "liblzma5" }, { "binary_version": "5.4.5-0.3", "binary_name": "liblzma5-dbgsym" }, { "binary_version": "5.4.5-0.3", "binary_name": "xz-utils" }, { "binary_version": "5.4.5-0.3", "binary_name": "xz-utils-dbgsym" }, { "binary_version": "5.4.5-0.3", "binary_name": "xzdec" }, { "binary_version": "5.4.5-0.3", "binary_name": "xzdec-dbgsym" } ], "priority_reason": "Results in a backdoor in sshd" }