Source: cve@mitre.org
Vulnerability in LAT/Telnet Gateway (lattelnet) on Ultrix 4.1 and 4.2 allows attackers to gain root privileges.
Critical vulnerability in the LAT/Telnet Gateway (lattelnet) on legacy Ultrix systems allows for complete system compromise. Successful exploitation grants attackers root privileges, enabling full control over the affected server and potential lateral movement within the network. This vulnerability poses a severe risk to any organization still operating vulnerable Ultrix systems.
Step 1: Target Identification: The attacker identifies a vulnerable Ultrix system running the lattelnet service.
Step 2: Packet Crafting: The attacker crafts a malicious packet, specifically designed to exploit the buffer overflow vulnerability. This packet contains a carefully constructed payload that will overwrite the stack.
Step 3: Packet Delivery: The attacker sends the crafted packet to the vulnerable lattelnet service, typically via the network.
Step 4: Vulnerability Trigger: The lattelnet service processes the malicious packet. Due to the lack of input validation, the packet's data overflows a buffer.
Step 5: Stack Corruption: The buffer overflow corrupts the stack, overwriting the return address of a function with a pointer to the attacker's injected code (shellcode).
Step 6: Code Execution: When the function returns, control is transferred to the attacker's shellcode, which executes with root privileges.
Step 7: Privilege Escalation: The shellcode typically establishes a root shell, giving the attacker complete control over the system.
The vulnerability stems from a flaw in the lattelnet service's handling of network traffic. Specifically, the code lacks proper input validation when processing data received from the LAT (Local Area Transport) or Telnet protocols. This allows an attacker to craft malicious packets that, when processed by lattelnet, trigger a buffer overflow. The overflow corrupts critical memory regions, including the stack, allowing the attacker to overwrite the return address of a function. By controlling the return address, the attacker can redirect program execution to arbitrary code, typically a shellcode payload, granting them root access. The root cause is a missing or inadequate bounds check on input data, leading to the buffer overflow condition.
Due to the age of the vulnerability and the target system, it's unlikely to be directly associated with specific APT groups. However, any threat actor with access to legacy systems or targeting specific historical data could leverage this. The vulnerability is not listed on the CISA KEV catalog due to the age and limited use of the affected systems.
Network traffic analysis: Look for unusual or malformed packets targeting TCP port 513 (or other ports used by lattelnet).
Log analysis: Examine system logs (e.g., syslog) for suspicious activity related to lattelnet, such as unexpected crashes or errors.
File integrity monitoring: Monitor critical system files for unauthorized modifications, especially those related to lattelnet and user accounts.
Memory forensics: If a compromise is suspected, perform memory analysis to identify injected code or evidence of a buffer overflow.
Host-based intrusion detection systems (HIDS) may detect suspicious process behavior or file modifications.
Isolate and segment the affected Ultrix systems from the rest of the network to limit the impact of a potential compromise.
If possible, migrate data and services from the vulnerable Ultrix systems to modern, patched operating systems.
Implement strong network segmentation to prevent lateral movement if the system is compromised.
Monitor network traffic for suspicious activity, especially traffic targeting the lattelnet service.
Regularly back up critical system data to ensure data recovery in case of a successful attack.
If the system must remain in operation, apply any available patches or workarounds (though these are unlikely to exist given the age of the system).