CVE-2016-9679 in Provisioning Services
Summary
by MITRE
Citrix Provisioning Services before 7.12 allows attackers to execute arbitrary code by overwriting a function pointer.
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Analysis
by VulDB Data Team • 05/14/2026
Citrix Provisioning Services version 7.11 and earlier contains a critical vulnerability that enables remote code execution through a function pointer overwrite flaw. This vulnerability resides in the software's handling of certain network protocols and data processing mechanisms. The flaw specifically manifests when the system processes incoming data that contains maliciously crafted function pointers, allowing an attacker to redirect execution flow and ultimately execute arbitrary code on the target system. The vulnerability stems from insufficient input validation and improper memory management within the provisioning service components. This issue represents a classic buffer overflow scenario where attacker-controlled data can overwrite critical function pointers, effectively hijacking the program's execution path. The vulnerability affects multiple Citrix Provisioning Services versions and has significant implications for enterprise environments that rely on this virtualization and provisioning technology.
The technical implementation of this vulnerability involves a specific memory corruption pattern where function pointers stored in memory structures are overwritten with attacker-controlled values. When the application attempts to invoke these corrupted function pointers, it executes code located at the attacker-specified memory addresses. This type of vulnerability falls under the common weakness enumeration CWE-121, which describes stack-based buffer overflow conditions. The flaw typically occurs during network communication processing where the application receives and processes data from remote clients without adequate validation of input boundaries. Attackers can exploit this by crafting malicious network packets that contain specially formatted data designed to overwrite the targeted function pointers. The attack vector is particularly dangerous because it can be executed remotely without requiring authentication, making it an attractive target for automated exploitation tools. The vulnerability is classified as a remote code execution flaw that operates at the application layer of the network stack.
The operational impact of CVE-2016-9679 extends beyond simple code execution capabilities to encompass full system compromise and potential lateral movement within enterprise networks. Organizations using affected Citrix Provisioning Services versions face significant risk of unauthorized access to their virtual desktop infrastructure and provisioning servers. The vulnerability can enable attackers to gain persistent access to critical infrastructure components, potentially allowing them to establish backdoors, exfiltrate sensitive data, or deploy additional malware. Security professionals should note that this vulnerability can be exploited in conjunction with other attack techniques to escalate privileges and move laterally across the network. The attack surface is particularly wide given that Citrix Provisioning Services is commonly used in enterprise environments for deploying and managing virtual desktops and servers. Organizations may experience service disruption, data breaches, and compliance violations if this vulnerability is successfully exploited. The impact is amplified by the fact that the vulnerability affects core provisioning functionality that many enterprises depend on for their virtualization infrastructure.
Mitigation strategies for CVE-2016-9679 should focus on immediate patching of affected systems and implementation of network segmentation controls. Organizations should prioritize updating to Citrix Provisioning Services version 7.12 or later, which contains the necessary security fixes for this vulnerability. Network administrators should implement strict firewall rules to limit access to provisioning services, particularly restricting communication to trusted networks and IP addresses. The implementation of intrusion detection systems can help identify exploitation attempts by monitoring for suspicious network traffic patterns associated with this vulnerability. Additional defensive measures include disabling unnecessary services, implementing least privilege access controls, and conducting regular security assessments of provisioning infrastructure. Security teams should also consider deploying application whitelisting solutions to prevent execution of unauthorized code on provisioning servers. The vulnerability's classification under ATT&CK technique T1059.007 for command and script interpreter indicates that attackers may attempt to establish persistence using command-line interfaces, making comprehensive monitoring essential. Organizations should also review their incident response procedures to ensure readiness for potential exploitation events, as this vulnerability can enable sophisticated attack campaigns targeting enterprise virtualization infrastructure.