Input validation error in lighttpd

1) Input validation error

EUVDB-ID: #VU33958

Risk: Medium

CVSSv3.1: 4.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C]

CVE-ID: CVE-2011-4362

CWE-ID: CWE-20 - Improper input validation

Exploit availability: Yes

Description

The vulnerability allows a remote non-authenticated attacker to perform service disruption.

Integer signedness error in the base64_decode function in the HTTP authentication functionality (http_auth.c) in lighttpd 1.4 before 1.4.30 and 1.5 before SVN revision 2806 allows remote attackers to cause a denial of service (segmentation fault) via crafted base64 input that triggers an out-of-bounds read with a negative index.

Mitigation

Install update from vendor's website.

Vulnerable software versions

lighttpd: 1.4.1 - 1.4.29

External links

http://archives.neohapsis.com/archives/bugtraq/2011-12/0167.html
http://blog.pi3.com.pl/?p=277
http://download.lighttpd.net/lighttpd/security/lighttpd_sa_2011_01.txt
http://redmine.lighttpd.net/issues/2370
http://secunia.com/advisories/47260
http://www.debian.org/security/2011/dsa-2368
http://www.exploit-db.com/exploits/18295
http://www.openwall.com/lists/oss-security/2011/11/29/13
http://www.openwall.com/lists/oss-security/2011/11/29/8
http://www.securitytracker.com/id?1026359
http://bugzilla.redhat.com/show_bug.cgi?id=758624
http://exchange.xforce.ibmcloud.com/vulnerabilities/71536

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.