bugGNU Mailutils - Bugs: bug #60937, mail(1) processing escape...


bug #60937: mail(1) processing escape sequences in bodies non-interactively

Submitter:  Hank Leininger <hlein>
Submitted:  Sun 18 Jul 2021 10:30:42 PM UTC
Category:  None Severity:  3 - Normal
Item Group:  None Status:  Fixed
Privacy:  Public Assigned to:  gray
Open/Closed:  Closed
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Sun 16 Jan 2022 04:39:18 AM UTC, comment #4: 

This commit was released in GNU mailutils version 3.13.

Paul Wise <pabs>
Wed 21 Jul 2021 09:37:26 AM UTC, comment #3: 

Yes, within a couple of weeks, when I finish incorporating other changes.

Sergey Poznyakoff <gray>
Group administrator
Wed 21 Jul 2021 04:50:33 AM UTC, comment #2: 

comment #1:

> Fixed in 4befcfd015256c568121653038accbd84820198f. Thank you.

Thanks! Are there any plans to make a release?

I ask because it makes it a lot easier to distribute fixes downstream (Gentoo for us) and we're keen because of the security impact here.

Sam James <thesamesam>
Mon 19 Jul 2021 08:32:22 AM UTC, comment #1: 

Fixed in 4befcfd015256c568121653038accbd84820198f. Thank you.

Sergey Poznyakoff <gray>
Group administrator
Sun 18 Jul 2021 10:30:42 PM UTC, original submission:  

mail(1) processes escape sequences in message bodies unless given -E 'set escape'. This is fine for interactive use, but non-interactively it seems like nothing but a bad surprise.

This creates a vulnerability any time some content under an attacker's control is piped to mailutils' mail, unless that -E option is added. Other mail(1) implementations have disabled escape sequences in non-interactive mode since at least ~2002, for instance:


A recent example of such mailutils behavior leading to an RCE vulnerability is https://github.com/fail2ban/fail2ban/security/advisories/GHSA-m985-3f3v-cwmm

fail2ban is treating that as a bug in their software, but it's a mailutils-specific bug, and a mailutils-specific fix, which breaks for any other mail(1) that doesn't use -E the same way.

Hank Leininger <hlein>


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    Follow 3 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2021-07-19 gray StatusNone Fixed
        Assigned toNone gray
        Open/ClosedOpen Closed

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