Input validation error in Libxml2

1) Input validation error

EUVDB-ID: #VU32389

Risk: Medium

CVSSv3.1: 4.6 [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-2015-7941

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows context-dependent attackers to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can cause a denial of service (out-of-bounds read and libxml2 crash) via crafted XML data to the (1) xmlParseEntityDecl or (2) xmlParseConditionalSections function in parser.c, as demonstrated by non-terminated entities. "context dependent" seems to point to MiTM attack due to: If a user or automated system were tricked into opening a specially crafted document, an attacker could possibly cause libxml2 to crash, resulting in a denial of service.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Apache Tomcat: 6.0.19

External links

http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177341.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177381.html
http://lists.opensuse.org/opensuse-updates/2015-12/msg00120.html
http://lists.opensuse.org/opensuse-updates/2016-01/msg00031.html
http://marc.info/?l=bugtraq&m=145382616617563&w=2
http://rhn.redhat.com/errata/RHSA-2015-2549.html
http://rhn.redhat.com/errata/RHSA-2015-2550.html
http://rhn.redhat.com/errata/RHSA-2016-1089.html
http://www.debian.org/security/2015/dsa-3430
http://www.openwall.com/lists/oss-security/2015/10/22/5
http://www.openwall.com/lists/oss-security/2015/10/22/8
http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
http://www.securityfocus.com/bid/74241
http://www.securitytracker.com/id/1034243
http://www.ubuntu.com/usn/USN-2812-1
http://xmlsoft.org/news.html
http://bugzilla.gnome.org/show_bug.cgi?id=744980
http://git.gnome.org/browse/libxml2/commit/?id=9b8512337d14c8ddf662fcb98b0135f225a1c489
http://git.gnome.org/browse/libxml2/commit/?id=a7dfab7411cbf545f359dd3157e5df1eb0e7ce31
http://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c04944172
http://security.gentoo.org/glsa/201701-37

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.