CVE-2019-1944 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 vulnerability identified as CVE-2019-1944 affects the smart tunnel functionality of Cisco Adaptive Security Appliance (ASA) devices, representing a critical security flaw that enables authenticated local attackers to escalate privileges to root level access or inject malicious library files during tunnel establishment. This vulnerability resides within the privilege escalation mechanisms of the ASA's smart tunnel implementation, specifically targeting the authentication and authorization processes that govern user access to system resources. The affected Cisco ASA models include various versions of the Adaptive Security Appliance software that incorporate the smart tunnel feature, making this a widespread concern across enterprise network security infrastructure. The vulnerability's classification aligns with CWE-269: Improper Privilege Management, which addresses weaknesses in privilege control mechanisms that allow unauthorized users to gain elevated access rights.
The technical exploitation of this vulnerability occurs through a combination of privilege escalation vectors and library loading mechanisms within the smart tunnel establishment process. An authenticated local attacker who possesses valid credentials for the ASA system can leverage this flaw to elevate their privileges to root level access, effectively gaining complete control over the device. Additionally, the vulnerability allows for the loading of malicious library files during the tunnel establishment phase, which can be used to execute arbitrary code with the highest system privileges. This dual exploitation capability makes the vulnerability particularly dangerous as it provides both privilege escalation and code execution capabilities. The attack surface is expanded by the fact that the vulnerability exists during the tunnel establishment process, meaning that even legitimate users who establish tunnels could inadvertently expose the system to malicious code injection if proper security controls are not in place.
The operational impact of CVE-2019-1944 extends beyond simple privilege escalation, as it fundamentally compromises the integrity and confidentiality of network security infrastructure. When an attacker gains root access to an ASA device, they can manipulate firewall rules, bypass security controls, monitor network traffic, and potentially establish persistent backdoors within the network. The ability to load malicious libraries during tunnel establishment creates a persistent threat vector that could remain undetected for extended periods, as the malicious code would be executed within the legitimate system processes. Organizations relying on ASA devices for network security would experience significant operational disruption, including potential data breaches, network monitoring failures, and complete loss of trust in their security infrastructure. The vulnerability also impacts the availability of network services, as attackers could potentially disable security features or corrupt system files, leading to complete device compromise and service outages.
Mitigation strategies for CVE-2019-1944 should focus on immediate patch deployment and comprehensive security hardening measures. Cisco has released security updates and patches specifically addressing this vulnerability, which organizations must apply immediately to prevent exploitation. Network administrators should implement strict access controls and monitoring of ASA device access, including logging and alerting for privilege escalation attempts. The principle of least privilege should be enforced, limiting local access to ASA devices to only essential personnel with valid business requirements. Additionally, organizations should implement network segmentation and monitoring to detect unauthorized tunnel establishment attempts and malicious library loading activities. The mitigation approach aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation and T1106: Native API, which addresses the exploitation of system vulnerabilities to gain elevated privileges. Regular security assessments and vulnerability scanning should be conducted to identify potential exploitation attempts, while network traffic monitoring should be enhanced to detect suspicious activities related to smart tunnel establishment and library loading processes. Organizations should also maintain detailed audit logs of all ASA device activities and implement intrusion detection systems specifically configured to identify exploitation attempts targeting this vulnerability class.