Vulnerability identifier: #VU6170

Vulnerability risk: Critical

CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2009-1391

CWE-ID: CWE-193

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Compress::Raw::Zlib
Client/Desktop applications / Software for archiving

Vendor: Perl

Description
The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to off-by-one error in Zlib.xs in Compress::Raw::Zlib Perl module before 2.017 when processing specially crafted zlib archives. A remote attacker can pass a specially crafted zlib archive to vulnerable application, trigger heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation may allow an attacker to compromise vulnerable system.

Note: this vulnerability is being actively exploited in the wild against AMaViS and SpamAssassin, which use vulnerable Perl module.

Mitigation
Update Compress::Raw::Zlib Perl module to version 2.017.

Vulnerable software versions

Compress::Raw::Zlib: 2.015

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External links
http://bugzilla.redhat.com/show_bug.cgi?id=504386
http://code.activestate.com/lists/activeperl/%3c00e401ca276c$9deaea50$d9c0bef0$@com%3e/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.