CVE-2001-1484 in ADSL Modem
Summary
by MITRE
Alcatel ADSL modems allow remote attackers to access the Trivial File Transfer Protocol (TFTP) to modify firmware and configuration via a bounce attack from a system on the local area network (LAN) side, which is allowed to access TFTP without authentication.
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Analysis
by VulDB Data Team • 11/17/2024
The vulnerability identified as CVE-2001-1484 affects Alcatel ADSL modems and represents a significant security flaw in network device configuration that enables unauthorized remote access through improperly secured Trivial File Transfer Protocol implementations. This vulnerability specifically targets the TFTP service running on these modems, which is designed to facilitate firmware updates and configuration management but has been configured without proper authentication mechanisms. The flaw allows attackers positioned on the local area network side of the device to exploit TFTP functionality and perform malicious operations including firmware modification and configuration changes that can compromise the entire network infrastructure.
The technical implementation of this vulnerability stems from the lack of authentication controls within the TFTP service running on the affected Alcatel modems. TFTP is a simple file transfer protocol that traditionally operates without user authentication, making it inherently vulnerable when deployed in unsecured environments. In this case, the modem's configuration allows any device on the local network to access TFTP services without requiring authentication credentials, creating a path for malicious actors to manipulate the device's operational parameters. The vulnerability is particularly concerning because it enables what is known as a bounce attack, where an attacker uses a compromised local system to indirectly access and manipulate the modem's TFTP service, effectively bypassing direct network restrictions that might otherwise prevent such access.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with the capability to modify critical firmware components and system configurations that govern how the modem operates within the network. When an attacker successfully exploits this vulnerability, they can replace the firmware with malicious versions that may include backdoors, logging capabilities, or other persistent access mechanisms that can remain undetected for extended periods. Configuration modifications can alter routing tables, disable security features, or redirect network traffic to malicious endpoints, potentially compromising the entire local network and creating persistent attack vectors that can be used for further network infiltration or data exfiltration activities.
The security implications of CVE-2001-1484 align with several common attack patterns documented in the MITRE ATT&CK framework, particularly those related to privilege escalation and persistence mechanisms. This vulnerability enables attackers to establish persistent access through firmware modification, which maps directly to ATT&CK technique T1064 for persistence through boot or logon initialization scripts and T1072 for application deployment. Additionally, the vulnerability's classification relates to CWE-284, which addresses improper access control in software systems, specifically focusing on insufficient authentication mechanisms that allow unauthorized access to critical system components. The attack vector described in this vulnerability also demonstrates characteristics of CWE-255, which covers issues with credential management and authentication processes that fail to properly validate user identities before granting access to sensitive functionality.
Organizations should implement immediate mitigation strategies including network segmentation to isolate critical network devices from general LAN access, disabling TFTP services on modems when not actively required for legitimate administrative functions, and implementing network monitoring to detect unauthorized TFTP access attempts. Regular firmware updates should be applied to ensure that vendors have addressed known security flaws, and network administrators should conduct thorough vulnerability assessments to identify similar insecure configurations across their entire network infrastructure. The implementation of network access controls and firewall rules that restrict TFTP access to only authorized administrative systems can effectively prevent exploitation of this vulnerability while maintaining legitimate operational requirements for firmware updates and configuration management.