CVE-2023-4744 in AC8
Summary
by MITRE • 09/04/2023
A vulnerability was found in Tenda AC8 16.03.34.06_cn_TDC01. It has been declared as critical. Affected by this vulnerability is the function formSetDeviceName. The manipulation leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-238633 was assigned to this vulnerability.
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Analysis
by VulDB Data Team • 09/29/2023
The vulnerability identified as CVE-2023-4744 represents a critical stack-based buffer overflow flaw within the Tenda AC8 wireless router firmware version 16.03.34.06_cn_TDC01. This vulnerability specifically affects the formSetDeviceName function, which handles device name configuration through web interface interactions. The flaw resides in how the firmware processes user-supplied input when setting device names, creating an opportunity for attackers to execute arbitrary code or cause system crashes. The vulnerability has been publicly disclosed and is actively being exploited, making it particularly dangerous for affected users who may be unaware of the security risk. The attack vector is remote, meaning that an unauthenticated attacker can exploit this vulnerability without requiring physical access to the device or network credentials. This remote exploit capability significantly expands the potential attack surface and increases the severity of the vulnerability.
The technical implementation of this buffer overflow stems from insufficient input validation within the formSetDeviceName function, which likely uses unsafe string handling methods such as strcpy or sprintf without proper bounds checking. When users submit device names through the web interface, the firmware fails to validate the length of the input before copying it into a fixed-size stack buffer. This allows attackers to overwrite adjacent memory locations, potentially corrupting the stack frame and enabling code execution. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which describes a condition where a program writes data past the end of a fixed-length buffer located on the stack. The attack can be executed through HTTP requests targeting the affected web interface, making it accessible to anyone who can reach the device's management interface over the network. The public availability of exploit code increases the likelihood of successful exploitation and reduces the barrier to entry for potential attackers.
The operational impact of this vulnerability extends beyond simple device compromise, as it can lead to complete system takeover and persistent backdoor access. An attacker who successfully exploits this vulnerability can gain full administrative control over the router, potentially enabling them to modify network configurations, intercept traffic, redirect DNS requests, or establish persistent access points. The router serves as a critical network gateway, making it an attractive target for attackers seeking to establish footholds within larger networks. The vulnerability affects not only individual users but also organizations that deploy these devices, as compromised routers can serve as launching points for broader attacks against internal networks. The stack-based nature of the overflow also makes the exploitation more reliable compared to heap-based vulnerabilities, as stack memory layout is more predictable. The remote exploit capability means that attackers can target vulnerable devices from anywhere on the internet, potentially affecting thousands of devices simultaneously if they are accessible to external networks.
Mitigation strategies for CVE-2023-4744 should prioritize immediate firmware updates from Tenda, as the vendor has likely released patches to address this specific vulnerability. Users should also implement network segmentation and firewall rules to limit access to router management interfaces, restricting access to trusted IP addresses only. Network monitoring should be enhanced to detect unusual traffic patterns or unauthorized configuration changes that might indicate exploitation attempts. Additional defensive measures include disabling unnecessary services, changing default administrative credentials, and implementing intrusion detection systems that can identify exploitation attempts targeting known vulnerabilities. The vulnerability demonstrates the importance of secure coding practices and input validation, as highlighted by ATT&CK technique T1210 for exploiting weaknesses in remote services. Organizations should also consider implementing device inventory tracking to identify all affected Tenda AC8 routers within their network infrastructure and prioritize their remediation. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network devices that may be susceptible to similar buffer overflow exploits.