PT-2021-17360 · NetGear · Netgear R7800

Takeshi · Published 2021-02-26 · Updated 2021-03-16 · CVE-2021-27256

Positive Technologies (AI Summary)

CVSS v3.1

8.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions: NETGEAR R7800 version 1.0.2.76

Description: This issue allows network-adjacent attackers to execute arbitrary code on affected installations. Although authentication is required to exploit this issue, the existing authentication mechanism can be bypassed. The specific flaw exists within the handling of the rc service parameter provided to "apply save.cgi". The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this issue to execute code in the context of root.

Recommendations: For NETGEAR R7800 version 1.0.2.76, as a temporary workaround, consider disabling the "apply save.cgi" endpoint until a patch is available. Restrict access to the rc service parameter to minimize the risk of exploitation. Avoid using the rc service parameter in the affected "apply save.cgi" endpoint until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this issue.

Fix

OS Command Injection

Weakness Enumeration

CWE-78

Related Identifiers

CVE-2021-27256

ZDI-21-262

Affected Products

Netgear R7800

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2021-27256 · Security Note
• https://zerodayinitiative.com/advisories/ZDI-21-262 · Security Note
• https://kb.netgear.com/000062883/Security-Advisory-for-Multiple-Vulnerabilities-on-Some-Routers-Satellites-and-Extenders · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-27256 · Vendor Advisory
• https://t.me/cibsecurity/24555 · Telegram Post
• https://t.me/cvenotify/10966 · Telegram Post