CVE-2022-29396 in N600R
Summary
by MITRE • 05/11/2022
TOTOLINK N600R V4.3.0cu.7647_B20210106 was discovered to contain a stack overflow via the comment parameter in the function FUN_00418f10.
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Analysis
by VulDB Data Team • 05/13/2022
The vulnerability identified as CVE-2022-29396 affects the TOTOLINK N600R router firmware version V4.3.0cu.7647_B20210106, representing a critical stack overflow condition that can be exploited through improper input validation within the device's web interface. This flaw exists within the function named FUN_00418f10 which processes user-supplied data through the comment parameter, creating an exploitable condition that allows attackers to manipulate the program's execution flow by overwriting stack memory. The stack overflow vulnerability specifically arises when the router fails to properly validate the length of input data submitted through the comment field, enabling an attacker to craft malicious payloads that exceed the allocated buffer space.
The technical implementation of this vulnerability demonstrates a classic buffer overflow scenario where the comment parameter in the web administration interface lacks adequate bounds checking mechanisms. When an attacker submits a specially crafted string through the comment field, the system attempts to copy this input into a fixed-size buffer without proper length verification, resulting in memory corruption that can be leveraged to execute arbitrary code or cause a denial of service condition. This flaw directly maps to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory locations including return addresses and stack canaries.
From an operational perspective, this vulnerability presents significant risk to network security as it allows remote code execution without authentication requirements, enabling attackers to gain full administrative control over the affected router. The impact extends beyond simple privilege escalation since the compromised device can serve as a pivot point for further network infiltration, DNS tunneling, or man-in-the-middle attacks against connected devices. Network defenders face particular challenges with this vulnerability as it affects consumer-grade networking equipment that typically lacks robust security monitoring capabilities and may remain unpatched for extended periods due to user unawareness or lack of automated update mechanisms.
The exploitation of this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, specifically targeting the use of web-based attack vectors to execute malicious code within the router's operating environment. Security professionals should consider implementing network segmentation measures to limit lateral movement if such devices are present in critical network zones, while also monitoring for unusual traffic patterns that might indicate exploitation attempts. Mitigation strategies include immediate firmware updates from TOTOLINK's official sources, network-based intrusion detection rules targeting the specific vulnerable parameter, and implementing web application firewalls to filter malicious input patterns before they reach the affected system. Organizations should also conduct comprehensive inventory assessments to identify all affected devices within their network infrastructure and prioritize remediation efforts based on risk exposure and network criticality.