XML External Entity injection in Jenkins Nuget plugin

1) XML External Entity injection

EUVDB-ID: #VU53588

Risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21658

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

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to insufficient validation of user-supplied XML input in the "Build on NuGet updates" feature. A remote attacker can pass a specially crafted XML code to the affected application and view contents of arbitrary files on the system or initiate requests to external systems.

Successful exploitation of the vulnerability may allow an attacker to view contents of arbitrary file on the server or perform network scanning of internal and external infrastructure.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Nuget: 0.1 - 1.0

CPE2.3

• cpe:2.3:a:jenkins:nuget:0.1:*:*:*:*:*:*:*
• cpe:2.3:a:jenkins:nuget:0.2:*:*:*:*:*:*:*
• cpe:2.3:a:jenkins:nuget:0.3:*:*:*:*:*:*:*

External links

https://www.jenkins.io/security/advisory/2021-05-25/#SECURITY-2340
https://www.openwall.com/lists/oss-security/2021/05/25/3

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.