Vulnerability identifier: #VU59057

Vulnerability risk: Medium

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-44224

CWE-ID: CWE-918

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Apache HTTP Server
Server applications / Web servers

Vendor: Apache Foundation

Description

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input in forward proxy configurations. A remote attacker can send a specially crafted HTTP request and trick the web server to initiate requests to arbitrary systems or cause NULL pointer dereference error and crash the web server.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

SSRF if possible for configuration that mix forward and reverse proxy.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache HTTP Server: 2.4.7 - 2.4.51

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External links
http://downloads.apache.org/httpd/CHANGES_2.4

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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.