CVE-2017-6768 in Application Policy Infrastructure Controller
Summary
by MITRE
A vulnerability in the build procedure for certain executable system files installed at boot time on Cisco Application Policy Infrastructure Controller (APIC) devices could allow an authenticated, local attacker to gain root-level privileges. The vulnerability is due to a custom executable system file that was built to use relative search paths for libraries without properly validating the library to be loaded. An attacker could exploit this vulnerability by authenticating to the device and loading a malicious library that can escalate the privilege level. A successful exploit could allow the attacker to gain root-level privileges and take full control of the device. The attacker must have valid user credentials to log in to the device. Cisco Bug IDs: CSCvc96087. Known Affected Releases: 1.1(0.920a), 1.1(1j), 1.1(3f); 1.2 Base, 1.2(2), 1.2(3), 1.2.2; 1.3(1), 1.3(2), 1.3(2f); 2.0 Base, 2.0(1).
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Analysis
by VulDB Data Team • 01/09/2021
This vulnerability exists within the build procedure of executable system files installed at boot time on Cisco Application Policy Infrastructure Controller devices, representing a critical privilege escalation flaw that undermines the security posture of these network infrastructure components. The vulnerability stems from improper handling of library loading mechanisms during the system build process, specifically when custom executable files utilize relative search paths without adequate validation of the libraries to be loaded. This design flaw creates an exploitable condition where an authenticated local attacker can manipulate the library loading sequence to execute malicious code with elevated privileges.
The technical implementation of this vulnerability leverages the principle of library path hijacking, where the system's dynamic linker resolves library dependencies using relative paths that may be manipulated by an attacker with local access. According to CWE-426, this corresponds to an untrusted search path vulnerability where the system fails to validate the integrity and authenticity of dynamically loaded libraries. The flaw specifically affects the build process of system files that are executed during device boot, making it particularly dangerous as these processes typically run with elevated privileges. When an attacker authenticates to the device with valid user credentials, they can leverage this vulnerability to load malicious libraries that exploit the relative path resolution mechanism, ultimately escalating privileges to root level.
The operational impact of this vulnerability is severe, as it provides attackers with complete control over affected Cisco APIC devices, which serve as critical network policy enforcement points in enterprise and data center environments. Once root privileges are obtained, attackers can modify system configurations, install backdoors, exfiltrate sensitive network policy data, or disrupt network operations. The vulnerability affects multiple software releases including versions 1.1(0.920a), 1.1(1j), 1.1(3f), 1.2 Base through 1.2(3), 1.3(1) through 1.3(2f), and 2.0 Base through 2.0(1), indicating a widespread exposure across the product line. This privilege escalation capability directly maps to ATT&CK technique T1068, which describes the exploitation of legitimate credentials to gain elevated privileges through system-level vulnerabilities.
Mitigation strategies must address both the immediate vulnerability and underlying architectural issues in the build process. Organizations should apply Cisco's official security patches and updates that correct the library loading behavior in affected releases. System administrators should implement strict access controls and monitor for unauthorized local access attempts, as the vulnerability requires valid credentials for exploitation. The remediation approach should include validating all system file integrity through checksum verification and implementing proper library path resolution that uses absolute paths or explicit validation mechanisms. Additionally, network segmentation and privilege separation practices should be enhanced to limit the potential impact of successful exploitation, particularly in environments where APIC devices control critical network policies and access controls.