(Pwn2Own) Cisco RV340 NGINX sessionid Directory Traversal Authentication Bypass Vulnerability

February 22nd, 2022
ZDI-22-409 ZDI-CAN-15610

CVE ID

CVE-2022-20705, CVE-2022-20707

CVSS Score

8.8 AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors

Cisco

Affected Products

RV340

Vulnerability Details

This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of Cisco RV340 routers. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the configuration of the NGINX web server. When parsing the sessionid cookie, the process does not properly validate a user-supplied path prior to using it in file operations. An attacker can leverage this vulnerability to bypass authentication on the system.

Additional Details

Cisco has issued an update to correct this vulnerability. More details can be found at:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-mult-vuln-KA9PK6D

Disclosure Timeline

  • 2021-11-24 - Vulnerability reported to vendor
  • 2022-02-22 - Coordinated public release of advisory

Credit

Bien Pham (@bienpnn) from Team Orca of Sea Security (security.sea.com)

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