CVE-2008-6561 in Presentation Server Client
Summary
by MITRE
Citrix Presentation Server Client for Windows before 10.200 does not clear "credential information" from process memory in unspecified circumstances, which might allow local users to gain privileges.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/11/2017
The vulnerability identified as CVE-2008-6561 affects Citrix Presentation Server Client for Windows versions prior to 10.200, representing a critical memory exposure issue that could potentially lead to privilege escalation. This flaw resides in the client application's handling of credential information within process memory, creating a persistent security risk that local attackers can exploit to gain elevated system privileges. The vulnerability stems from improper memory management practices where sensitive authentication data remains accessible in memory even after the authentication process should have completed, violating fundamental security principles of credential handling and memory sanitization.
The technical implementation of this vulnerability involves the Citrix client application failing to properly clear credential information from memory during specific operational scenarios. When users authenticate through the Citrix Presentation Server Client, authentication tokens and credential data are temporarily stored in process memory to facilitate session management and connection establishment. However, in affected versions, this credential information persists in memory beyond the legitimate session lifecycle, creating a memory dump or memory inspection opportunity for local adversaries. This memory persistence allows attackers to extract sensitive credential data through various means including direct memory access, process inspection tools, or specialized memory analysis utilities. The vulnerability manifests in unspecified circumstances, suggesting that certain operational conditions or authentication workflows trigger the improper memory retention, making the vulnerability particularly challenging to predict and mitigate.
From an operational perspective, this vulnerability presents significant risk to enterprise environments where Citrix Presentation Server Client is deployed across multiple systems. Local users with access to compromised systems can leverage this memory exposure to extract authentication credentials that may include usernames, passwords, or token information used for accessing Citrix servers and underlying network resources. The privilege escalation potential means that attackers who successfully extract credential information could gain access to additional systems or resources that were previously protected by authentication barriers. This vulnerability particularly impacts organizations that rely heavily on Citrix infrastructure for remote access and application delivery, as the extracted credentials could provide access to enterprise applications, databases, or other sensitive systems that depend on the Citrix client for connectivity.
The security implications of this vulnerability align with CWE-200, which addresses information exposure through improper memory handling, and can be mapped to ATT&CK technique T1003.001 for credential dumping and T1059.001 for command and scripting interpreter usage. Organizations should implement immediate mitigation strategies including applying the vendor-provided security patches for Citrix Presentation Server Client version 10.200 or later, which address the memory clearing functionality. Additionally, system administrators should monitor for unauthorized local access to systems running affected Citrix clients, implement memory protection mechanisms, and consider network segmentation to limit the potential impact of credential exposure. Regular vulnerability assessments and security audits should be conducted to identify systems running outdated Citrix client versions, while security monitoring solutions should be configured to detect unusual memory access patterns or credential-related activities that might indicate exploitation attempts. The remediation process requires careful consideration of the patch deployment impact on existing Citrix infrastructure and user workflows to ensure continued operational effectiveness while addressing the memory exposure vulnerability.