Re: Heap Overflow in PCRE

[Fabian Keil <freebsd-listen () fabiankeil de>]

Hanno Böck <hanno () hboeck de> wrote:

> https://blog.fuzzing-project.org/29-Heap-Overflow-in-PCRE.html
>
> The Perl Compatible Regular Expressions (PCRE) library has just
> released a new version which fixes a number of security issues.
>
> Fuzzing the pcretest tool uncovered an input leading to a heap overflow
> in the function pcre_exec. This bug was found with the help of american
> fuzzy lop and address sanitizer.
> https://bugs.exim.org/show_bug.cgi?id=1637 Upstream bug #1637 (PoC and
> ASAN trace attached there)
>
> This is fixed in PCRE 8.38. There are two variants of PCRE, the classic
> one and PCRE2. PCRE2 is not affected.
> https://lists.exim.org/lurker/message/20151123.125009.80e5ac05.en.html
>
> Appart from that a couple of other vulnerabilities found by other
> people have been fixed in this release:
> https://bugs.exim.org/show_bug.cgi?id=1672
> Heap overflow in compile_regex
> https://bugs.exim.org/show_bug.cgi?id=1515
> Stack overflow in compile_regex
> https://bugs.exim.org/show_bug.cgi?id=1667
> Heap overflow in compile_regex
>
> If you use PCRE to parse untrusted inputs you should update immediately.

The last sentence seems overly broad to me as many (most?) applications
use trusted PCRE patterns (that get parsed and executed) to parse untrusted
input.

For this use case the issues above don't seem to require immediate action.

Fabian

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