CVE-2017-2786 in PopUp Printer Client
Summary
by MITRE
A denial of service vulnerability 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 an out of bounds read causing a crash and a denial of service.
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Analysis
by VulDB Data Team • 09/05/2020
The CVE-2017-2786 vulnerability represents a critical denial of service flaw within the Pharos PopUp printer client software version 9.0 specifically affecting the psnotifyd application component. This vulnerability resides in the printer management infrastructure that facilitates communication between print devices and client systems. The Pharos PopUp printer client serves as a bridge for managing print jobs and notifications in enterprise environments, making this vulnerability particularly concerning for organizations relying on robust printing infrastructure. The vulnerability manifests through improper input validation within the psnotifyd daemon responsible for handling printer notification events and system communications.
The technical exploitation of this vulnerability occurs through a carefully crafted network packet that triggers an out of bounds read condition within the psnotifyd application memory management. This type of flaw represents a classic buffer overread vulnerability where the application attempts to access memory locations beyond the allocated buffer boundaries. The out of bounds read condition causes the psnotifyd process to terminate unexpectedly, resulting in a complete system crash of the printer notification service. This memory corruption vulnerability directly maps to CWE-125 which defines out-of-bounds read conditions as a fundamental class of memory safety issues. The vulnerability's impact is amplified by the fact that it operates at the network level, allowing remote attackers to exploit the flaw without requiring local system access or authentication credentials.
The operational consequences of CVE-2017-2786 extend beyond simple service disruption to potentially compromise entire print management workflows within affected organizations. When the psnotifyd application crashes, it prevents legitimate printer notifications from being processed, which can lead to delayed print job processing, missed alerts about printer status changes, and complete failure of print queue management functions. This denial of service condition affects not only individual users attempting to print documents but also IT administrators who rely on the notification system for monitoring and managing print infrastructure. The vulnerability creates a cascading effect where printer jobs may queue indefinitely or fail completely, disrupting business operations and productivity. Organizations using the Pharos PopUp client in mission-critical environments face significant risk of operational disruption, particularly in high-volume printing environments where notification systems are essential for monitoring print device status and managing print job workflows.
Mitigation strategies for CVE-2017-2786 should focus on immediate patching of the affected Pharos PopUp client software to version 9.1 or later, which contains the necessary fixes for the out of bounds read vulnerability. Network-level protections including firewall rules that restrict access to the psnotifyd service ports and implementing network segmentation can provide temporary mitigation while patches are deployed. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, making it important for security teams to monitor for unusual network traffic patterns or service disruptions related to print management systems. Additionally, implementing application whitelisting policies that restrict execution of unauthorized printer client components can prevent exploitation of similar vulnerabilities in the future. Organizations should also consider implementing intrusion detection systems that can identify malformed packets attempting to exploit this specific vulnerability pattern, as the attack vector relies on sending specifically crafted network payloads that would be detectable through network traffic analysis.