CVE-2019-1945 in ASA
Summary
by MITRE
Multiple vulnerabilities in the smart tunnel functionality of Cisco Adaptive Security Appliance (ASA) could allow an authenticated, local attacker to elevate privileges to the root user or load a malicious library file while the tunnel is being established. For more information about these vulnerabilities, see the Details section of this security advisory.
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Analysis
by VulDB Data Team • 11/21/2023
The Cisco Adaptive Security Appliance (ASA) smart tunnel functionality contains critical privilege escalation vulnerabilities that pose significant risks to network security infrastructure. These vulnerabilities exist within the ASA's tunnel establishment process and specifically target the local authentication mechanisms that govern access to the device's underlying operating system. The flaw allows an authenticated attacker with local access to escalate their privileges to root level, effectively granting complete control over the ASA device. Additionally, the vulnerability permits the loading of malicious library files during the tunnel creation phase, enabling arbitrary code execution and potential persistence within the network security infrastructure. This represents a fundamental compromise of the device's integrity and security posture, as the attacker can manipulate core system components while establishing network connections through the smart tunnel feature.
The technical implementation of these vulnerabilities stems from insufficient input validation and privilege management within the ASA's smart tunnel subsystem. When establishing a smart tunnel, the system fails to properly validate the authentication context and does not adequately enforce privilege boundaries during the library loading process. This creates an attack surface where local authenticated users can manipulate the tunnel establishment sequence to gain elevated privileges or inject malicious code into the system. The vulnerability specifically affects the ASA software versions that support smart tunnel functionality, with the attack vector requiring local access to the device and valid authentication credentials. The flaw represents a classic privilege escalation vulnerability where the system's access controls are bypassed during a specific operational phase of the tunnel establishment process. This issue aligns with CWE-269 Privilege Management Problems and CWE-426 Untrusted Search Path, as the system fails to properly manage privileges and validates input during critical operations.
The operational impact of these vulnerabilities extends beyond immediate privilege escalation to encompass broader network security implications. Once an attacker achieves root access through these vulnerabilities, they can modify firewall rules, disable security features, monitor network traffic, and potentially establish backdoors for continued access. The ability to load malicious library files during tunnel establishment provides attackers with persistent access mechanisms that can survive system reboots and normal operational procedures. Network administrators face significant challenges in detecting such attacks, as the malicious activities occur within legitimate network operations and can be easily concealed. The vulnerability affects organizations relying on ASA devices for network security, potentially compromising the entire network infrastructure that depends on these security appliances for traffic filtering and access control. Attackers can leverage these vulnerabilities to conduct advanced persistent threats, data exfiltration, or network reconnaissance activities while remaining undetected within the network perimeter.
Mitigation strategies for these vulnerabilities require immediate attention from network security teams to protect their ASA infrastructure. The primary recommendation involves applying the latest security patches and updates provided by Cisco to address the privilege escalation flaws in the smart tunnel functionality. Organizations should implement strict access controls and limit local authentication credentials to only essential personnel with verified identities. Network segmentation and monitoring should be enhanced to detect unusual tunnel establishment patterns that might indicate exploitation attempts. The implementation of network access control lists and firewall rules can help restrict access to ASA management interfaces and limit the attack surface. Security teams should also conduct regular vulnerability assessments and penetration testing to identify potential exploitation vectors and ensure proper patch management processes are in place. Additionally, implementing behavioral monitoring solutions that can detect anomalous privilege escalation activities or library loading operations during tunnel establishment can provide early warning capabilities. The use of network intrusion detection systems with signatures specific to these vulnerabilities can further enhance detection capabilities. Organizations should also review and update their incident response procedures to ensure rapid response to potential exploitation attempts, as these vulnerabilities could enable attackers to establish persistent access to critical network infrastructure.