Vulnerability identifier: #VU64055

Vulnerability risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:U/RC:C]

CVE-ID: N/A

CWE-ID: CWE-93

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
USG100
Client/Desktop applications / Antivirus software/Personal firewalls
USG200
Client/Desktop applications / Antivirus software/Personal firewalls
USG300
Client/Desktop applications / Antivirus software/Personal firewalls
USG20W
Client/Desktop applications / Antivirus software/Personal firewalls
USG20
Client/Desktop applications / Antivirus software/Personal firewalls
USG50
Client/Desktop applications / Antivirus software/Personal firewalls

Vendor: ZyXEL Communications Corp.

Description

The vulnerability allows a remote attacker to inject arbitrary data in server response.

The vulnerability exists due to insufficient validation of attacker-supplied data in the CGI program. A remote attacker can pass specially crafted data to the application containing CR-LF characters and modify application behavior.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

USG100: All versions

USG200: All versions

USG300: All versions

USG20W: All versions

USG20: All versions

USG50: All versions

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External links
http://www.zyxel.com/support/Zyxel-security-advisory-for-CRLF-injection-vulnerability-in-some-legacy-firewalls.shtml

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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.