CVE-2021-20162 in AC2600 TEW-827DRU
Summary
by MITRE • 12/31/2021
Trendnet AC2600 TEW-827DRU version 2.08B01 stores credentials in plaintext. Usernames and passwords are stored in plaintext in the config files on the device. For example, /etc/config/cameo contains the admin password in plaintext.
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Analysis
by VulDB Data Team • 01/05/2022
This vulnerability represents a critical security flaw in Trendnet AC2600 TEW-827DRU routers running firmware version 2.08B01 where administrative credentials are stored in plaintext within configuration files. The issue stems from poor cryptographic practices in credential storage implementation, specifically exposing administrative passwords in clear text format within the /etc/config/cameo file. This configuration file serves as a persistent storage location for router administration credentials, making it accessible to any local attacker with file system access or those who can obtain physical access to the device. The vulnerability directly violates security best practices outlined in the OWASP Top Ten and aligns with CWE-312, which specifically addresses the exposure of sensitive information through plaintext storage. From an operational perspective, this flaw creates a significant attack surface that allows unauthorized individuals to gain administrative control over the router, potentially leading to complete network compromise.
The technical exploitation of this vulnerability requires minimal prerequisites since the credentials are stored in plain text format without any form of encryption or obfuscation. An attacker with access to the device's file system or physical access can simply read the configuration file to extract administrative credentials. This weakness is particularly concerning because it enables persistent access to the network infrastructure, allowing adversaries to modify router settings, redirect traffic, implement man-in-the-middle attacks, or establish backdoors for continued access. The vulnerability operates at the application layer and affects the device's configuration management system, creating a fundamental security failure in the router's credential handling mechanisms. According to ATT&CK framework, this represents a privilege escalation technique through credential access, specifically mapping to T1552 and T1078 where attackers can leverage stored credentials to maintain persistent access to network resources.
The impact of this vulnerability extends beyond simple credential exposure, as it enables a wide range of malicious activities including network reconnaissance, traffic interception, and potential lateral movement within the network. Attackers can use the compromised administrative credentials to modify firewall rules, disable security features, or redirect network traffic to malicious endpoints. The plaintext storage of credentials also means that even if the device is powered off or rebooted, the credentials remain accessible to anyone with file system access. Organizations deploying these routers face significant risk of unauthorized network access, data breaches, and potential compromise of the entire network infrastructure. Mitigation strategies should include immediate firmware updates from Trendnet to address the plaintext credential storage issue, implementation of network segmentation to limit the impact of potential compromise, and regular security assessments to identify similar vulnerabilities in network infrastructure devices. Additionally, network administrators should consider implementing network access controls and monitoring systems to detect unauthorized access attempts to router management interfaces, as this vulnerability creates a persistent backdoor for attackers who can obtain physical access to the device.