CVE-2011-3211 in Bcfg2
Summary
by MITRE
The server in Bcfg2 1.1.2 and earlier, and 1.2 prerelease, allows remote attackers to execute arbitrary commands via shell metacharacters in data received from a client.
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Analysis
by VulDB Data Team • 11/20/2021
The vulnerability identified as CVE-2011-3211 represents a critical command injection flaw within the Bcfg2 configuration management system. This issue affects versions 1.1.2 and earlier, as well as 1.2 prerelease versions of the software. Bcfg2 serves as a configuration management tool that enables administrators to manage and deploy system configurations across multiple machines, making it a critical component in enterprise environments. The vulnerability stems from insufficient input validation and sanitization mechanisms within the server component, which processes data received from client machines.
The technical flaw manifests when the Bcfg2 server receives data from clients that contains shell metacharacters such as semicolons, ampersands, or backticks. These characters, when improperly handled, can be interpreted by the underlying shell as command delimiters or execution operators, leading to arbitrary code execution. The vulnerability occurs because the server fails to properly sanitize or escape input data before processing it within shell contexts. This type of flaw aligns with CWE-78, which specifically addresses "Improper Neutralization of Special Elements used in an OS Command" and represents a classic command injection vulnerability that can be exploited by remote attackers without authentication.
The operational impact of this vulnerability is severe and far-reaching for organizations relying on Bcfg2 for system management. Remote attackers can leverage this weakness to execute arbitrary commands on affected servers with the privileges of the Bcfg2 service account. This could potentially lead to complete system compromise, data exfiltration, or use of the compromised server as a pivot point for attacking other systems within the network. The vulnerability affects the integrity and confidentiality of the entire configuration management infrastructure, as attackers could modify system configurations, install malicious software, or gain persistent access to the environment. Given that Bcfg2 is designed to manage multiple client systems, a successful exploitation could enable attackers to spread their influence across an entire organization's infrastructure.
Mitigation strategies for this vulnerability should focus on immediate remediation through version upgrades to Bcfg2 1.2 or later, where the command injection vulnerability has been addressed. Organizations should also implement network segmentation to limit access to Bcfg2 servers and ensure that only authorized clients can communicate with the management system. Input validation and sanitization should be strengthened at all levels of the application, particularly where shell commands are constructed from user-provided data. Security monitoring should be enhanced to detect suspicious patterns in client communications, and access controls should be tightened to prevent unauthorized access to the configuration management system. This vulnerability demonstrates the importance of proper input validation and the principle of least privilege in security design, aligning with ATT&CK techniques related to command and control through exploitation of remote services and privilege escalation through configuration management systems. Organizations should also consider implementing web application firewalls and intrusion detection systems to help detect and prevent exploitation attempts against such vulnerabilities.