CVE-2026-47116 in LTK3500SF
Summary
by MITRE • 09/22/2026
LTSecurity LTK3500SF contains a hard-coded credentials vulnerability where root and guest account passwords are stored as reversible hashes in /etc/shadow, recoverable using dictionary-based cracking tools. Attackers can use the recovered credentials to authenticate via Telnet or SSH and obtain full root-level access to the operating system.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/22/2026
The LTSecurity LTK3500SF network device suffers from a critical hard-coded credential vulnerability that fundamentally compromises its authentication security model. This flaw is rooted in the improper storage of sensitive authentication data, specifically for both the privileged root account and the standard guest account. Instead of utilizing secure hashing algorithms with salt to protect password integrity, these credentials are stored as reversible hashes within the /etc/shadow file on the device's operating system. The use of reversible encryption or weak hash functions means that the original plaintext passwords can be directly derived from their stored representations without requiring computationally expensive brute-force attacks. This architectural decision represents a severe deviation from industry best practices for credential management, exposing users to immediate and trivial compromise if an attacker gains any level of access to the file system.
The technical mechanism behind this vulnerability allows adversaries to easily extract these reversible hashes using standard forensic tools or by exploiting other minor vulnerabilities that permit read access to local files. Once extracted, the passwords can be decrypted instantly due to their reversible nature, eliminating the need for dictionary-based cracking in most cases, although such tools remain effective against any residual weak hashing components. This ease of recovery transforms a static configuration error into an active exploitation vector. The presence of these hard-coded credentials implies that they are likely identical across all units of this model manufactured by LTSecurity, creating a widespread risk where compromising one device may provide insights for attacking others in the same deployment environment.
The operational impact of this vulnerability is severe, as it enables unauthorized actors to bypass authentication mechanisms entirely and gain full administrative control over the device. Attackers can leverage the recovered root credentials to authenticate via remote management protocols such as Telnet or SSH. Gaining access through these interfaces provides complete command-line control, allowing the attacker to execute arbitrary commands, modify system configurations, install persistent backdoors, or pivot into other parts of the network infrastructure. Since the root account possesses unrestricted privileges, this level of access effectively results in a total compromise of the device's confidentiality, integrity, and availability. The guest account credentials further expand the attack surface by allowing initial low-privilege access that can often be escalated to root through local privilege escalation techniques if additional vulnerabilities exist.
This vulnerability aligns with CWE-798: Use of Hard-coded Credentials, which describes situations where authentication information is embedded directly into source code or configuration files rather than being managed securely at runtime. It also relates closely to CWE-256: Unprotected Storage of Credentials, as the reversible hashing fails to provide adequate protection for sensitive data at rest. From a threat intelligence perspective, this behavior facilitates initial access and privilege escalation techniques documented in the MITRE ATT&CK framework, particularly those involving valid accounts obtained through credential dumping or brute force attacks that are trivially simplified by the weak storage mechanism. The ability to authenticate via Telnet also highlights risks associated with CWE-319: Cleartext Transmission of Passwords if the protocol itself is not secured, although the primary flaw here remains the static and reversible nature of the stored passwords themselves.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. In the short term, administrators should immediately change all default credentials to strong, unique passwords that are not derived from common dictionaries or patterns if possible, though this may be difficult if the firmware does not allow changing root passwords securely. More critically, LTSecurity needs to issue a firmware update that replaces the reversible hashing mechanism with a secure, salted cryptographic hash function such as bcrypt, scrypt, or Argon2 for password storage. The device should also enforce mandatory credential rotation policies and disable unnecessary services like Telnet in favor of more secure alternatives like SSH with key-based authentication where feasible. Network segmentation is recommended to limit the exposure of these devices to untrusted networks until patches are applied. Regular vulnerability assessments and penetration testing focused on default credentials can help identify similar issues across an organization's IoT infrastructure, ensuring that hard-coded secrets do not serve as a persistent entry point for attackers.