CVE-2022-25074 in TL-WR902AC
Summary
by MITRE • 02/24/2022
TP-Link TL-WR902AC(US)_V3_191209 routers were discovered to contain a stack overflow in the function DM_ Fillobjbystr(). This vulnerability allows unauthenticated attackers to execute arbitrary code.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 02/26/2022
The TP-Link TL-WR902AC(US)_V3_191209 router firmware contains a critical stack overflow vulnerability within the DM_Fillobjbystr() function that represents a significant security risk for network infrastructure. This vulnerability resides in the router's web management interface handling code where improper input validation occurs during the processing of user-supplied data. The stack overflow condition arises when the firmware fails to properly validate the length of incoming data before copying it into a fixed-size buffer on the stack, creating an exploitable condition that can be leveraged by remote attackers without authentication requirements.
The technical flaw manifests in the DM_Fillobjbystr() function which processes objects and strings received through the web interface, particularly when handling malformed or excessively long input parameters. This function does not perform adequate bounds checking or length validation before copying data into local stack buffers, allowing attackers to overwrite adjacent stack memory locations. The vulnerability follows the common pattern of stack-based buffer overflow attacks that can be exploited to overwrite return addresses, function pointers, or other critical stack data structures. According to the CWE database, this maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a high-risk vulnerability category due to its potential for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple remote code execution as it provides attackers with complete control over the affected router's functionality. An unauthenticated attacker can leverage this vulnerability to gain root access to the device, potentially leading to man-in-the-middle attacks, network traffic interception, DNS hijacking, or the installation of persistent backdoors. The attack surface is particularly concerning given that the vulnerability affects a widely deployed consumer-grade router model, making it a prime target for automated exploitation campaigns. The lack of authentication requirements means that any internet-facing device running this firmware version is immediately at risk, creating a significant exposure for both individual users and enterprise networks that may unknowingly include these devices.
Mitigation strategies for this vulnerability should include immediate firmware updates from TP-Link to address the stack overflow condition in the DM_Fillobjbystr() function. Network administrators should implement network segmentation to isolate affected devices and monitor for suspicious traffic patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1071.004 for Application Layer Protocol to establish persistence and maintain access. Organizations should also consider implementing intrusion detection systems that can identify exploitation attempts targeting this specific vulnerability and establish monitoring protocols for unusual router behavior. Additionally, disabling unnecessary services and ensuring proper network access controls can help reduce the attack surface while awaiting official patches.