Vulnerability identifier: #VU53532

Vulnerability risk: Medium

CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23937

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Apache Wicket
Universal components / Libraries / Software for developers

Vendor: Apache Foundation

Description

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

The vulnerability exists due to insufficient validation of user-supplied input in WebClientInfo when processing the "X-Forwarded-For" HTTP header. A remote attacker can force the server to initiate numerous DNS lookups and overload the internal DNS server.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Wicket: 7.0.0 - 9.2.0

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External links
http://seclists.org/oss-sec/2021/q2/161

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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.