CVE-2014-2913 in openSUSE
Summary
by MITRE
** DISPUTED ** Incomplete blacklist vulnerability in nrpe.c in Nagios Remote Plugin Executor (NRPE) 2.15 and earlier allows remote attackers to execute arbitrary commands via a newline character in the -a option to libexec/check_nrpe. NOTE: this issue is disputed by multiple parties. It has been reported that the vendor allows newlines as "expected behavior." Also, this issue can only occur when the administrator enables the "dont_blame_nrpe" option in nrpe.conf despite the "HIGH security risk" warning within the comments.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/06/2024
The vulnerability described in CVE-2014-2913 represents a critical security flaw in the Nagios Remote Plugin Executor (NRPE) version 2.15 and earlier systems. This issue manifests as an incomplete blacklist vulnerability within the nrpe.c component that processes command-line arguments for the check_nrpe utility. The vulnerability specifically occurs when the -a option is utilized with libexec/check_nrpe, creating a potential remote code execution vector that could be exploited by malicious actors. The nature of this vulnerability places it squarely within the realm of command injection attacks where unauthorized commands can be executed on the target system.
The technical flaw stems from inadequate input validation mechanisms within the NRPE implementation that fails to properly sanitize command arguments containing newline characters. When a newline character is included in the -a parameter, the system's parsing logic can be manipulated to execute unintended commands. This behavior exploits a fundamental weakness in the access control and input filtering mechanisms that should prevent arbitrary command execution. The vulnerability operates at the application layer and leverages the trust relationship between the monitoring system and remote hosts, making it particularly dangerous in networked environments where proper authentication and authorization controls are expected.
The operational impact of this vulnerability extends beyond simple command execution, as it can potentially allow attackers to gain full control over systems running vulnerable NRPE versions. The security implications are severe because NRPE is commonly used in enterprise environments for remote system monitoring, making this vulnerability a prime target for attackers seeking persistent access to critical infrastructure. The risk is further amplified when considering that the vulnerability requires specific configuration conditions to be exploitable, particularly the enabling of the "dont_blame_nrpe" option in nrpe.conf despite explicit security warnings. This configuration requirement demonstrates how poor security practices and inadequate administrative oversight can compound the impact of underlying software vulnerabilities.
Organizations should implement multiple layers of defense to mitigate this vulnerability, including immediate disabling of the problematic configuration option, implementing strict network segmentation, and applying the latest available patches from the vendor. The vulnerability aligns with CWE-77 and CWE-78 categories, which specifically address command injection flaws and improper input validation respectively. From an attack perspective, this vulnerability maps to several ATT&CK techniques including privilege escalation and execution through remote services, making it particularly dangerous in environments where monitoring systems have elevated privileges. Security professionals should also consider implementing network monitoring to detect suspicious command execution patterns and establish strict access controls for NRPE configuration files to prevent unauthorized modifications that could enable exploitation.