CVE-2022-25073 in TL-WR841N
Summary
by MITRE • 02/24/2022
TL-WR841Nv14_US_0.9.1_4.18 routers were discovered to contain a stack overflow in the function dm_fillObjByStr(). This vulnerability allows unauthenticated attackers to execute arbitrary code.
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Analysis
by VulDB Data Team • 02/26/2022
The TL-WR841Nv14_US_0.9.1_4.18 router firmware contains a critical stack overflow vulnerability within the dm_fillObjByStr() function that presents a significant security risk to network infrastructure. This vulnerability falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflows that occur when insufficient bounds checking is performed on data copied into fixed-size stack buffers. The flaw exists in the router's firmware implementation where user-controllable input is processed without adequate validation, creating an exploitable condition that can be leveraged by remote attackers.
The technical implementation of this vulnerability demonstrates how improper input handling in embedded networking equipment can lead to complete system compromise. When the dm_fillObjByStr() function processes incoming data, it fails to validate the length of input parameters before copying them into stack-allocated buffers. This oversight allows an attacker to craft malicious input that exceeds the buffer capacity, causing a stack overflow condition that can overwrite adjacent memory locations including return addresses and control data. The vulnerability is particularly dangerous because it requires no authentication credentials to exploit, making it accessible to any remote attacker who can send crafted packets to the affected device.
From an operational perspective, this vulnerability creates a severe risk for network administrators and end users who rely on these routers for network connectivity. The ability to execute arbitrary code remotely without authentication means that attackers can gain complete control over the affected routers, potentially enabling them to redirect traffic, install malware, or use the device as a pivot point for attacking other systems within the network. This represents a direct violation of the principle of least privilege and undermines the fundamental security assumptions of network infrastructure devices. The attack surface extends beyond simple code execution to include potential denial of service conditions and data exfiltration capabilities.
Security mitigations for this vulnerability should focus on immediate firmware updates from the vendor to address the buffer overflow condition in the dm_fillObjByStr() function. Network administrators should implement network segmentation and monitoring to detect unusual traffic patterns that might indicate exploitation attempts. Additionally, implementing network access control lists and disabling unnecessary services on affected devices can reduce the attack surface. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow attackers to execute arbitrary commands on the affected device. Organizations should also consider deploying intrusion detection systems that can identify patterns associated with stack overflow exploitation attempts and establish incident response procedures to address potential compromise of network infrastructure devices.