CVE-2015-0663 in AnyConnect Secure Mobility Client
Summary
by MITRE
Cisco AnyConnect Secure Mobility Client 4.0(.00051) and earlier does not properly implement access control for IPC messages, which allows local users to write to arbitrary files via crafted messages, aka Bug ID CSCus79392.
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Analysis
by VulDB Data Team • 04/15/2022
The vulnerability identified as CVE-2015-0663 affects Cisco AnyConnect Secure Mobility Client version 4.0(.00051) and earlier releases, representing a critical access control flaw within the client's inter-process communication mechanism. This vulnerability stems from insufficient validation of IPC messages, creating a pathway for local attackers to manipulate file system operations through maliciously crafted communication payloads. The flaw specifically impacts the client's handling of inter-process communication channels, where proper access controls should prevent unauthorized file write operations but instead allow arbitrary file modification. The vulnerability is catalogued under the Cisco Bug ID CSCus79392, which provides additional context for the specific implementation issue within the AnyConnect client architecture. This type of vulnerability represents a fundamental breakdown in the principle of least privilege, where local users can escalate their privileges through manipulation of legitimate IPC mechanisms that are intended to facilitate secure communication between different components of the client application.
The technical exploitation of this vulnerability relies on the client's improper implementation of access control checks within its IPC message handling system. When the AnyConnect client processes incoming IPC messages, it fails to validate the source or content of these messages properly, allowing local malicious users to craft specially formatted messages that trigger unintended file system operations. This flaw enables attackers to write data to arbitrary locations within the file system, potentially allowing them to modify critical application files, inject malicious code, or manipulate configuration settings. The vulnerability specifically targets the client's IPC mechanism which is designed to allow secure communication between different processes within the application, but due to inadequate access control implementation, these communication channels become attack vectors for local privilege escalation. The flaw essentially creates a backdoor through which local users can bypass normal file system access controls and write to locations that should normally be restricted to authorized processes or users.
The operational impact of CVE-2015-0663 extends beyond simple local privilege escalation, as it can enable attackers to compromise the integrity of the entire AnyConnect client installation. Local users who exploit this vulnerability can potentially modify core client components, inject malicious code into the application, or alter configuration files that control the client's behavior and security policies. This can lead to persistent access, data exfiltration, or further escalation of privileges within the system. The vulnerability is particularly concerning because it allows local attackers to manipulate files that may be used for authentication, encryption, or other security-critical functions within the AnyConnect environment. The impact is compounded by the fact that AnyConnect clients are commonly deployed in enterprise environments where they provide secure remote access to corporate networks, making this vulnerability potentially exploitable for broader network compromise. This type of vulnerability aligns with CWE-284, which addresses improper access control in software implementations, and represents a clear violation of the principle that processes should only be able to access resources they are authorized to modify.
Organizations should implement immediate mitigation strategies to address this vulnerability, including applying the latest security patches from Cisco that address the IPC access control implementation flaw. The recommended approach involves updating the AnyConnect client to versions that properly implement access controls for IPC messages and validate all incoming communication payloads. System administrators should also consider implementing additional monitoring and logging of file system operations that occur during AnyConnect client execution, as this can help detect potential exploitation attempts. The vulnerability's classification under ATT&CK technique T1068, which covers local privilege escalation, indicates that organizations should review their local account security policies and ensure that only authorized users have access to systems running vulnerable AnyConnect clients. Additionally, network segmentation and access control measures should be implemented to limit the potential impact of successful exploitation, as attackers who gain access through this vulnerability could potentially use the compromised client as a foothold for further network infiltration. Regular security assessments and vulnerability scanning should include verification of AnyConnect client versions to ensure that the specific IPC access control flaw has been remediated and that proper access controls are in place for all inter-process communication within the application.