CVE-2018-1111 in Red Hat
Summary
by MITRE
DHCP packages in Red Hat Enterprise Linux 6 and 7, Fedora 28, and earlier are vulnerable to a command injection flaw in the NetworkManager integration script included in the DHCP client. A malicious DHCP server, or an attacker on the local network able to spoof DHCP responses, could use this flaw to execute arbitrary commands with root privileges on systems using NetworkManager and configured to obtain network configuration using the DHCP protocol.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2018-1111 represents a critical command injection flaw within the DHCP client implementation of several Linux distributions including Red Hat Enterprise Linux versions 6 and 7, as well as Fedora 28 and earlier releases. This security weakness resides in the NetworkManager integration script that processes DHCP packages, creating a pathway for attackers to execute arbitrary commands with elevated privileges. The flaw fundamentally compromises the integrity of network configuration processes that rely on DHCP protocols, particularly affecting systems where NetworkManager is actively managing network connections and DHCP is used for automatic configuration.
The technical implementation of this vulnerability stems from insufficient input validation within the DHCP client's NetworkManager integration component. When the DHCP client receives network configuration data from a server, the integration script fails to properly sanitize or escape command parameters that may be embedded within DHCP options or responses. This lack of proper sanitization creates an environment where attacker-controlled data can be interpreted as executable commands rather than benign configuration parameters. The vulnerability specifically manifests when the DHCP client processes certain DHCP options that contain command strings, allowing malicious actors to inject shell commands that execute with root privileges due to the elevated permissions required for network configuration management.
The operational impact of CVE-2018-1111 extends beyond simple privilege escalation to encompass full system compromise capabilities. An attacker positioned within the same local network segment or capable of spoofing DHCP responses can exploit this vulnerability to gain complete control over affected systems. The implications include potential data exfiltration, persistent backdoor installation, lateral movement within network infrastructure, and complete system takeover. Systems running NetworkManager with DHCP configuration enabled become prime targets, as the vulnerability affects not just individual machines but entire network segments where DHCP is the primary configuration mechanism. This makes the flaw particularly dangerous in enterprise environments where DHCP is commonly used for network management and where the attack surface includes numerous potentially vulnerable endpoints.
The exploitation of this vulnerability aligns with several ATT&CK framework techniques including privilege escalation through command injection and network service enumeration. From a CWE perspective, this represents a classic command injection vulnerability classified under CWE-77, which specifically addresses situations where untrusted data is incorporated into command execution contexts without proper sanitization. The vulnerability also intersects with CWE-20, which covers input validation failures that can lead to various injection attacks, and CWE-121, which addresses buffer overflow conditions that may enable command execution. Organizations should implement immediate patching strategies targeting the specific NetworkManager DHCP client integration scripts, while also considering network segmentation and DHCP snooping mechanisms to prevent unauthorized DHCP server activities. Additional mitigations include disabling unnecessary DHCP client features, implementing network access controls, and monitoring for anomalous DHCP traffic patterns that might indicate exploitation attempts.