Rule Category

PROTOCOL-TELNET -- Snort has detected traffic that may indicate the presence of the telnet protocol or vulnerabilities in the telnet protocol on the network.

Alert Message

PROTOCOL-TELNET login buffer non-evasive overflow attempt

Rule Explanation

This event is generated when an attempt is made to exploit a known buffer overflow vulnerability affecting "login" via Telnet. Impact: Serious. Unauthorized administrative access to the target host. Details: The login binary is used when establishing an interactive session on a system. It is used locally and by protocols that allow remote access. A buffer overflow condition exists in some versions of login that can be triggered by the manipulation of environment variables. This event is generated when an attempt is made to overflow login via telnet by manipulating the TTYPROMPT environment variable. Ease of Attack: Simple

What To Look For

Known Usage

No public information

False Positives

No known false positives


Cisco Talos Intelligence Group

MITRE ATT&CK Framework



For reference, see the MITRE ATT&CK vulnerability types here:


Rule Vulnerability

CVE Additional Information

Buffer overflow in login in various System V based operating systems allows remote attackers to execute arbitrary commands via a large number of arguments through services such as telnet and rlogin.
SeverityHIGH Base Score10.0
Impact Score10.0 Exploit Score10.0
Confidentiality ImpactCOMPLETE Integrity ImpactCOMPLETE
Availability ImpactCOMPLETE Access Vector
AuthenticationNONE Ease of Access