Bug 1998621 (CVE-2021-40153) - CVE-2021-40153 squashfs-tools: unvalidated filepaths allow writing outside of destination
Summary: CVE-2021-40153 squashfs-tools: unvalidated filepaths allow writing outside of...
Keywords:
Status: NEW
Alias: CVE-2021-40153
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Nobody
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Depends On: 2000637 1998622 2000638 2000656
Blocks: 1998293
TreeView+ depends on / blocked
 
Reported: 2021-08-27 18:20 UTC by Guilherme de Almeida Suckevicz
Modified: 2023-09-22 21:18 UTC (History)
4 users (show)

Fixed In Version: squashfs-tools 4.5
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in Squashfs-tools, where it is vulnerable to attacks similar to zip-slip. During extraction, a file can escape the destination directory either via the '../' string to access the parent directory or via symlinks. This flaw allows a specially crafted squashfs archive to install or overwrite files outside of the destination directory.
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Description Guilherme de Almeida Suckevicz 2021-08-27 18:20:35 UTC 
squashfs_opendir in unsquash-1.c in Squashfs-Tools versions before 4.5 stores the filename in the directory entry; this is then used by unsquashfs to create the new file during the unsquash. The filename is not validated for traversal outside of the destination directory, and thus allows writing to locations outside of the destination.

Reference:
https://github.com/plougher/squashfs-tools/issues/72

Upstream patch:
https://github.com/plougher/squashfs-tools/commit/79b5a555058eef4e1e7ff220c344d39f8cd09646
Comment 1 Guilherme de Almeida Suckevicz 2021-08-27 18:20:51 UTC 
Created squashfs-tools tracking bugs for this issue:

Affects: fedora-all [bug 1998622]
Comment 2 Fedora Update System 2021-08-30 20:41:47 UTC 
FEDORA-2021-cdbd827c1e has been pushed to the Fedora 34 stable repository.
If problem still persists, please make note of it in this bug report.
Comment 6 Fedora Update System 2021-09-29 01:07:59 UTC 
FEDORA-2021-9fb6da134f has been pushed to the Fedora 33 stable repository.
If problem still persists, please make note of it in this bug report.
Comment 7 Bruno Wolff III 2021-10-06 06:24:22 UTC 
The fix is now in all current versions of Fedora.
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