CVE-2018-0147 in Secure Access Control System
Summary
by MITRE
A vulnerability in Java deserialization used by Cisco Secure Access Control System (ACS) prior to release 5.8 patch 9 could allow an unauthenticated, remote attacker to execute arbitrary commands on an affected device. The vulnerability is due to insecure deserialization of user-supplied content by the affected software. An attacker could exploit this vulnerability by sending a crafted serialized Java object. An exploit could allow the attacker to execute arbitrary commands on the device with root privileges. Cisco Bug IDs: CSCvh25988.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2018-0147 represents a critical security flaw in Cisco Secure Access Control System versions prior to 5.8 patch 9, where insecure deserialization practices create a remote code execution vector. This vulnerability stems from the improper handling of user-supplied serialized Java objects within the ACS software framework, which operates as a network access control solution. The flaw allows unauthenticated remote attackers to exploit the system by sending specially crafted serialized Java objects that trigger arbitrary code execution on the affected device. The vulnerability is particularly concerning because it provides attackers with root-level privileges, enabling complete system compromise without requiring authentication credentials or prior access to the network infrastructure.
The technical implementation of this vulnerability aligns with common insecure deserialization patterns that have been extensively documented in cybersecurity literature and classified under CWE-502, which specifically addresses "Deserialization of Untrusted Data." The vulnerability exists because the affected Cisco ACS software does not properly validate or sanitize serialized Java objects received from network connections. When these objects are deserialized, they can contain malicious code that executes within the context of the running Java application, bypassing normal security controls and access restrictions. This deserialization process occurs without adequate input validation or object type checking, creating a pathway for attackers to inject malicious payloads that are then executed with the privileges of the Java process, typically running with elevated system permissions.
The operational impact of CVE-2018-0147 extends beyond simple remote code execution to encompass complete system compromise and potential network infiltration. Attackers exploiting this vulnerability can gain root access to affected Cisco ACS devices, which typically serve as critical network access control points managing user authentication and authorization policies. This compromise allows attackers to modify access control lists, create unauthorized user accounts, redirect network traffic, or establish persistent backdoors within the network infrastructure. The vulnerability's remote nature means that attackers can exploit it from outside the network perimeter without requiring physical access or legitimate credentials, making it particularly dangerous for organizations that rely on Cisco ACS for network security. The exploitation can occur through various network protocols that the ACS system accepts, potentially affecting multiple attack vectors including HTTP, HTTPS, or other management interfaces.
Organizations should implement immediate mitigations including applying Cisco's official patch 5.8 patch 9 or later versions that address the insecure deserialization vulnerability. Network segmentation and firewall rules should be configured to restrict access to ACS management interfaces, particularly limiting access to trusted IP ranges and implementing additional authentication layers. The implementation of network monitoring solutions that can detect unusual deserialization patterns or malformed serialized objects can provide additional defense-in-depth measures. Security teams should also consider disabling unnecessary services and protocols that may expose the vulnerable deserialization functionality, while conducting thorough network scans to identify all affected devices. According to ATT&CK framework category T1059, which covers Command and Scripting Interpreter, this vulnerability enables adversaries to execute commands through the established remote access channel. Organizations should also consider implementing application whitelisting policies and runtime application self-protection measures to prevent unauthorized code execution even if the underlying vulnerability cannot be immediately patched. Regular security assessments and vulnerability scanning should be performed to identify similar insecure deserialization patterns in other applications within the network infrastructure, as these vulnerabilities are common across various software platforms and can provide similar remote code execution capabilities.