Vulnerability identifier: #VU32838

Vulnerability risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2011-4539

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
DHCP
Server applications / Other server solutions

Vendor: ISC

Description

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

dhcpd in ISC DHCP 4.x before 4.2.3-P1 and 4.1-ESV before 4.1-ESV-R4 does not properly handle regular expressions in dhcpd.conf, which allows remote attackers to cause a denial of service (daemon crash) via a crafted request packet.

Mitigation
Install update from vendor's website.

Vulnerable software versions

DHCP: 4.0 - 4.0.3, 4.1-esv - 4.1.2, 4.2.0 - 4.2.8, 4.3.0 - 4.3.6-P1, 4.4.0 - 4.4.1

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External links
http://lists.fedoraproject.org/pipermail/package-announce/2011-December/070980.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-January/071549.html
http://lists.opensuse.org/opensuse-updates/2011-12/msg00006.html
http://secunia.com/advisories/47153
http://secunia.com/advisories/47178
http://security.gentoo.org/glsa/glsa-201301-06.xml
http://www.debian.org/security/2012/dsa-2519
http://www.mandriva.com/security/advisories?name=MDVSA-2011:182
http://www.securityfocus.com/bid/50971
http://www.securitytracker.com/id?1026393
http://www.ubuntu.com/usn/USN-1309-1
http://exchange.xforce.ibmcloud.com/vulnerabilities/71680
http://www.isc.org/software/dhcp/advisories/cve-2011-4539

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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?

No. We are not aware of malware exploiting this vulnerability.