CVE-2022-29377 in A3600R
Summary
by MITRE • 05/24/2022
Totolink A3600R V4.1.2cu.5182_B20201102 was discovered to contain a stacker overflow in the fread function at infostat.cgi. This vulnerability allows attackers to cause a Denial of Service (DoS) via the parameter CONTENT_LENGTH.
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Analysis
by VulDB Data Team • 05/29/2022
The vulnerability identified as CVE-2022-29377 affects the Totolink A3600R router firmware version V4.1.2cu.5182_B20201102, representing a critical stack buffer overflow condition within the infostat.cgi web interface component. This flaw resides in the fread function implementation, where insufficient input validation permits maliciously crafted data to overwrite adjacent memory locations on the stack. The vulnerability specifically manifests when processing the CONTENT_LENGTH parameter, which is typically used to indicate the size of data being transmitted to the router's web server. The stack overflow occurs because the application fails to properly bounds-check the incoming data before copying it into a fixed-size buffer, creating an exploitable condition that can be leveraged by remote attackers.
The operational impact of this vulnerability extends beyond simple denial of service, as the stack buffer overflow can potentially lead to arbitrary code execution or complete system compromise. When an attacker sends a specially crafted CONTENT_LENGTH value that exceeds the allocated buffer size, the overflow corrupts the stack memory structure, including return addresses and function pointers. This memory corruption can cause the web server process to crash and restart, resulting in persistent denial of service conditions that disrupt network connectivity for all devices relying on the router. The vulnerability is particularly concerning because it operates at the application layer of the network stack, allowing remote exploitation without requiring physical access or authentication credentials, thus aligning with ATT&CK technique T1210 for exploitation of remote services.
From a security standards perspective, this vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental weakness in software design that allows attackers to overwrite adjacent memory locations. The issue also relates to CWE-770 Allocation of Resources Without Limits or Throttling, as the application does not properly limit the size of data processed from the CONTENT_LENGTH parameter. The attack surface is widened by the fact that the vulnerability exists in a web-based administrative interface, making it accessible over the network and potentially exploitable by automated scanning tools. The lack of proper input validation in the infostat.cgi component represents a failure to implement proper security controls as recommended by the OWASP Top Ten and NIST cybersecurity frameworks, particularly in the area of input validation and resource management.
Mitigation strategies for CVE-2022-29377 should prioritize immediate firmware updates from the vendor, as Totolink has likely released patches addressing this specific vulnerability. Network administrators should implement network segmentation to isolate critical network infrastructure from potentially compromised devices, while also deploying intrusion detection systems to monitor for suspicious CONTENT_LENGTH parameter values. The implementation of web application firewalls can provide additional protection by filtering malicious requests before they reach the vulnerable web interface. Additionally, disabling unnecessary web services and administrative interfaces when not actively needed can reduce the attack surface. Regular security assessments should include verification of firmware versions and testing for similar buffer overflow vulnerabilities in other network devices, as this type of flaw commonly exists in embedded systems due to resource constraints and legacy code implementation practices. The vulnerability demonstrates the critical importance of proper memory management and input validation in embedded network devices, where the consequences of such flaws can extend far beyond simple service disruption to potentially compromise entire network infrastructures.