Vulnerability identifier: #VU48620

Vulnerability risk: Low

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

CVE-ID: CVE-2020-29299

CWE-ID: CWE-77

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ZyXEL ZLD
Hardware solutions / Firmware
ZeXEL SD-OS
Hardware solutions / Firmware

Vendor: ZyXEL Communications Corp.

Description

The vulnerability allows a remote user to execute arbitrary commands on the system.

The vulnerability exists due to insufficient validation of user supplied input n the “chg_exp_pwd” CGI program on some Zyxel security firewalls. A remote authenticated user can inject and execute arbitrary OS commands with elevated privileges.

Mitigation

Install updates from vendor's website.

Affected series	Patch available in
VPN series	On-premise: ZLD V4.39 week38* and above Orchestrator: SD-OS V10.03 week32* and above
USG series	ZLD V4.39 week38* and above
USG FLEX series	ZLD V4.55 week38* and above
ATP series	ZLD V4.55 week38* and above
NSG series	V1.33 patch 4** and above

Vulnerable software versions

ZyXEL ZLD: All versions

ZeXEL SD-OS: All versions

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External links
http://www.zyxel.com/support/Zyxel-security-advisory-for-command-injection-vulnerability-of-firewalls.shtml

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.