CVE-2019-6972 in TL-WR1043ND V2
Summary
by MITRE
An issue was discovered on TP-Link TL-WR1043ND V2 devices. The credentials can be easily decoded and cracked by brute-force, WordList, or Rainbow Table attacks. Specifically, credentials in the "Authorization" cookie are encoded with URL encoding and base64, leading to easy decoding. Also, the username is cleartext, and the password is hashed with the MD5 algorithm (after decoding of the URL encoded string with base64).
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 10/06/2023
The vulnerability identified in TP-Link TL-WR1043ND V2 devices represents a critical authentication weakness that undermines the security posture of network infrastructure equipment. This issue affects the web-based management interface of the router, where authentication credentials are improperly handled, creating multiple attack vectors for unauthorized access. The vulnerability stems from inadequate cryptographic practices and poor implementation of credential storage mechanisms, making it particularly dangerous for enterprise and home network environments where these devices are commonly deployed.
The technical flaw manifests in the improper handling of authentication tokens within the "Authorization" cookie, which employs a weak encoding scheme combining URL encoding with base64 encoding. This double encoding approach provides minimal security protection since both URL encoding and base64 encoding are easily reversible operations that do not constitute cryptographic security. The username field remains in cleartext format, while the password undergoes MD5 hashing after the base64 decoding process, creating a particularly vulnerable scenario where attackers can readily reconstruct the original credentials through simple decoding operations. This implementation violates fundamental security principles outlined in CWE-312 (Cleartext Storage of Sensitive Information) and CWE-326 (Inadequate Encryption Strength) by storing sensitive data in an easily reversible format.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to gain full administrative control over the router configuration, potentially leading to man-in-the-middle attacks, DNS hijacking, or the establishment of persistent backdoors within the network. The vulnerability's exploitability is significantly enhanced by the fact that MD5 hashing, while not cryptographically secure for modern applications, can be efficiently cracked using rainbow table attacks or brute-force methods due to its lack of salt and weak cryptographic properties. This weakness aligns with ATT&CK technique T1212 (Exploitation for Credential Access) and demonstrates how weak cryptographic implementations can compromise entire network security infrastructures. Network administrators who rely on these devices for critical network operations face substantial risk of unauthorized access and potential data breaches.
Mitigation strategies for this vulnerability require immediate action including firmware updates from TP-Link, which should implement proper cryptographic practices such as salted password hashing using modern algorithms like bcrypt, scrypt, or PBKDF2. Network segmentation and access control measures should be implemented to limit exposure, while monitoring systems should be deployed to detect unauthorized access attempts. The device should be configured to disable unnecessary services and restrict access to the management interface to trusted IP addresses only. Additionally, regular security audits should verify that authentication mechanisms are properly implemented and that no cleartext credentials are stored or transmitted within the network infrastructure. Organizations should also consider implementing network access control lists and intrusion detection systems to monitor for suspicious authentication attempts that may indicate exploitation of this vulnerability.