CVE-2017-2788 in PopUp Printer Client
Summary
by MITRE
A buffer overflows exists in the psnotifyd application of the Pharos PopUp printer client version 9.0. A specially crafted packet can be sent to the victim's computer and can lead to a heap based buffer overflow resulting in potential remote code execution. This client is always listening, has root privileges, and requires no user interaction to exploit.
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Analysis
by VulDB Data Team • 09/05/2020
The vulnerability identified as CVE-2017-2788 represents a critical heap-based buffer overflow flaw within the psnotifyd component of Pharos PopUp printer client version 9.0. This issue manifests in a manner that allows remote attackers to execute arbitrary code on targeted systems through the transmission of specially crafted packets. The psnotifyd application operates continuously as a background service, maintaining listening capabilities at all times, which fundamentally increases the attack surface and exploitability of this vulnerability. The flaw resides in the application's failure to properly validate input data received through network communications, creating a condition where maliciously formatted data can overwrite adjacent memory locations in the heap allocation space. This particular vulnerability operates under the Common Weakness Enumeration framework as CWE-121, classified as Stack-based Buffer Overflow, though the heap-based nature of the overflow specifically aligns with CWE-122, Heap-based Buffer Overflow, demonstrating the complexity of memory corruption vulnerabilities in modern applications.
The operational impact of this vulnerability extends far beyond typical network-based attacks due to the privileged execution context of the affected application. The psnotifyd process runs with root privileges, meaning successful exploitation would grant attackers complete system control without requiring additional privilege escalation techniques. The absence of user interaction requirements eliminates the need for social engineering or deceptive practices, making this vulnerability particularly dangerous in enterprise environments where printer systems are commonly accessible across network segments. Attackers can leverage this flaw to establish persistent backdoors, exfiltrate sensitive data, or deploy additional malicious payloads without detection, as the legitimate service continues to operate normally while serving as a covert channel for malicious activity. The continuous listening nature of the application ensures that exploitation can occur at any time during the system's uptime, providing attackers with persistent access windows.
Security professionals should implement immediate mitigations including network segmentation to isolate printer services from critical systems, firewall rules to restrict access to the specific ports used by psnotifyd, and application whitelisting to prevent unauthorized execution of the vulnerable client software. The most effective remediation approach involves updating to the latest version of the Pharos PopUp printer client where the buffer overflow has been patched and proper input validation has been implemented. Organizations should also consider disabling the psnotifyd service entirely if its functionality is not required, as this eliminates the attack surface entirely. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as the root privileges provide direct access to system-level operations. Additionally, the persistent nature of the vulnerability aligns with T1566.001 for Phishing and T1071.004 for Application Layer Protocol, as attackers can leverage this to maintain access while using legitimate network protocols for command and control communications. Regular security assessments and network monitoring should specifically target the identification of running instances of this vulnerable software to prevent exploitation attempts.
The broader implications of this vulnerability highlight the critical importance of securing print management systems, which are often overlooked in security assessments despite serving as potential entry points for attackers. Printer client software frequently runs with elevated privileges to facilitate proper device communication and management functions, creating inherent security risks when proper input validation and memory management practices are not implemented. This vulnerability demonstrates how seemingly minor flaws in network services can result in catastrophic security breaches, particularly when the services operate with administrative privileges and maintain persistent listening capabilities. Organizations must recognize that printer ecosystems represent complex attack surfaces requiring comprehensive security controls, including regular patch management, network access controls, and continuous monitoring for unauthorized printer client installations. The vulnerability also underscores the need for robust software development practices including input validation, memory safety checks, and privilege separation to prevent similar issues from occurring in future software releases.