Denial of service in expat

1) Improper Restriction of XML External Entity Reference

EUVDB-ID: #VU7242

Risk: Low

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-9233

CWE-ID: CWE-611 - Improper Restriction of XML External Entity Reference ('XXE')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an error within entityValueInitProcessor() function while parsing malformed XML in an external entity. An attacker can take advantage of this flaw to cause a denial of service against an application using the Expat library.

Successful exploitation of the vulnerability may allow an attacker to perform a denial of service attack.

Mitigation

Update to version 2.2.1.

Vulnerable software versions

expat: 1.95.0 - 2.2.0

External links

http://github.com/libexpat/libexpat/commit/c4bf96bb51dd2a1b0e185374362ee136fe2c9d7f
http://libexpat.github.io/doc/cve-2017-9233/

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.