SunOS Telnet Privilege Escalation

HIGH (7.2) Patch Available Patch Patch

Threat Intelligence

Low Risk
EPSS Score: 0.08% chance of exploitation (percentile: 25%)
🔍 Detection Tools: None available in major open-source tools
⚔️ Exploit Availability: No public exploits found

How we test →

What is it?

SunOS 4.1.1 and earlier versions of the in.telnetd software allow local users to gain root privileges by exploiting a vulnerability in the telnet protocol. This could potentially lead to unauthorized access to sensitive system resources.

Am I affected?

You're affected if you use SunOS version 4.1.1 or earlier. Check with: telnet -v (to see if the version is 4.1.1) or uname -a | grep sunos (to check for the operating system).

Note: This vulnerability does not affect modern Unix-like systems, including Linux and macOS.

Affected Products

Sun Microsystems / in.telnetd

How to fix

Patch: Download the patch from http://www.cert.org/advisories/CA-1991-02.html.
- Immediate mitigations:
- Restrict root access to sensitive resources (e.g., /etc/passwd).
- Monitor for suspicious login attempts.