Change History (8)
follow-up: 5 comment:1 by , 7 years ago
| Owner: | changed from to |
|---|---|
| Priority: | normal → high |
| Status: | new → assigned |
comment:2 by , 7 years ago
In fact, upstream have released 3.22.2, 3.20.2 to fix this in those series, it's only people using older versions that will need patches.
comment:3 by , 7 years ago
Stalled, for the moment I cannot build nautilus which we (correctly) recommend - for my own systems I work around that in configure, but it would be better to match the book.
follow-up: 7 comment:4 by , 7 years ago
Back in business, using autoconf-archive to get ax_require_defined.m4 for nautilus.
comment:5 by , 7 years ago
Replying to ken@…:
The fix appears to use libarchive to unarchive cbt files.
I was mistaken - cbt files are no-longer supported, only cbz, cb7.
comment:7 by , 7 years ago
Replying to ken@…:
Back in business, using autoconf-archive to get ax_require_defined.m4 for nautilus.
And Wayne spotted that was only referenced because I'd run autoreconf : at some point we needed that for a patch, I had neglected to remove it.
Bug fixes:
Like (I guess) most people, I thought that the vulnerability was obscure (I've never seen any of these comics .cbt files). But the description from the Arch advisory implies that for people using e.g. chrome (I suppose that means chromium) or epiphany could be susceptible:
[quote]The comic book backend in evince <= 3.24.0 is vulnerable to a command injection bug that can be used to execute arbitrary commands when a cbt file is opened.
CBT files are simple tar archives containing images. When a cbt file is processed, evince calls "tar -xOf $archive $filename" for every image file in the archive. While both the archive name and the filename are quoted to not be interpreted by the shell, the filename is completely attacker controlled an can start with "--" which leads to tar interpreting it as a command line flag. This can be exploited by creating a tar archive with an embedded file named something like this: "--checkpoint-action=exec=bash -c 'touch ~/covfefe.evince;'.jpg" This can presumably be triggered by the evince thumbnailer, which is not sandboxed, and web browsers that allow untrusted websites to auto- downloading files without user interaction (Chrome, Epiphany) can trigger the thumbnailer to run so this is web exposed." [endquote]
The fix appears to use libarchive to unarchive cbt files.
The vulnerability also applies to earlier versions - ubuntu produced fixes for their older versions a few days ago which disable CBT support.