CVE-2011-5227 in Netsight
Summary
by MITRE
Stack-based buffer overflow in the Syslog service (nssyslogd.exe) in Enterasys Network Management Suite (NMS) before 4.1.0.80 allows remote attackers to execute arbitrary code via a long PRIO field in a message to UDP port 514.
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Analysis
by VulDB Data Team • 05/27/2025
The vulnerability identified as CVE-2011-5227 represents a critical stack-based buffer overflow flaw within the Syslog service component of Enterasys Network Management Suite. This vulnerability specifically affects the nssyslogd.exe process which handles syslog message processing on UDP port 514, making it a significant threat to network infrastructure security. The flaw stems from inadequate input validation mechanisms that fail to properly constrain the length of the PRIO field in syslog messages, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access.
The technical implementation of this vulnerability involves the manipulation of the PRIO field within syslog messages, which is a standard component used to indicate the priority and facility of log messages. When an attacker sends a specially crafted syslog message containing an excessively long PRIO field to the vulnerable UDP port 514, the nssyslogd.exe process fails to properly validate the input length before copying it into a fixed-size stack buffer. This buffer overflow condition allows the attacker to overwrite adjacent memory locations, potentially corrupting the stack frame and enabling arbitrary code execution with the privileges of the running service. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which is a well-documented and highly dangerous class of vulnerability that has been extensively catalogued in the CWE database.
From an operational perspective, this vulnerability presents a severe risk to network management systems since it allows remote code execution without requiring authentication, making it particularly attractive to attackers. The attack surface is broad as any system running the affected Enterasys NMS version and listening on UDP port 514 becomes a potential target. The impact extends beyond simple privilege escalation as successful exploitation can lead to complete system compromise, data exfiltration, and the establishment of persistent backdoors within the network infrastructure. Network security teams must consider this vulnerability as a high-priority threat since it can be exploited from external networks and requires minimal reconnaissance to identify vulnerable targets.
The exploitation of CVE-2011-5227 aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and execution phases. Attackers can leverage this vulnerability as part of a broader attack chain that may include reconnaissance activities to identify vulnerable systems followed by exploitation to establish a foothold. The vulnerability also relates to privilege escalation techniques since successful exploitation typically results in elevated system privileges. Organizations should consider implementing network segmentation to isolate critical systems running vulnerable versions of Enterasys NMS, while also ensuring that UDP port 514 is properly firewalled and monitored for unusual traffic patterns. The recommended mitigation strategy involves upgrading to Enterasys NMS version 4.1.0.80 or later, which includes proper input validation and buffer size constraints that prevent the exploitation of this vulnerability. Additionally, network administrators should implement logging and monitoring solutions to detect potential exploitation attempts and consider disabling syslog services if they are not essential for operations.