CVE-2021-41072 - Improper Link Resolution Before File Access ('Link Following')

Severity

81%

Complexity

27%

Confidentiality

86%

squashfs_opendir in unsquash-2.c in Squashfs-Tools 4.5 allows Directory Traversal, a different vulnerability than CVE-2021-40153. A squashfs filesystem that has been crafted to include a symbolic link and then contents under the same filename in a filesystem can cause unsquashfs to first create the symbolic link pointing outside the expected directory, and then the subsequent write operation will cause the unsquashfs process to write through the symbolic link elsewhere in the filesystem.

CVSS 3.1 Base Score 8.1. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H).

CVSS 2.0 Base Score 5.8. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:N/I:P/A:P).

Overview

First reported 3 years ago

2021-09-14 01:15:00

Last updated 3 years ago

2021-11-05 18:09:00

Affected Software

Debian Linux 9.0

9.0

References

https://github.com/plougher/squashfs-tools/issues/72#issuecomment-913833405

https://github.com/plougher/squashfs-tools/commit/e0485802ec72996c20026da320650d8362f555bd

https://github.com/plougher/squashfs-tools/issues/72#issuecomment-913833405

Exploit, Third Party Advisory

https://github.com/plougher/squashfs-tools/commit/e0485802ec72996c20026da320650d8362f555bd

Patch, Third Party Advisory

DSA-4987

[debian-lts-announce] 20211020 [SECURITY] [DLA 2789-1] squashfs-tools security update

DSA-4987

Third Party Advisory

[debian-lts-announce] 20211020 [SECURITY] [DLA 2789-1] squashfs-tools security update

Mailing List, Third Party Advisory

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