CVE-2019-1766 in IP Phone 8800
Summary
by MITRE
A vulnerability in the web-based management interface of Session Initiation Protocol (SIP) Software for Cisco IP Phone 8800 Series could allow an unauthenticated, remote attacker to cause high disk utilization, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software does not restrict the maximum size of certain files that can be written to disk. An attacker who has valid administrator credentials for an affected system could exploit this vulnerability by sending a crafted, remote connection request to an affected system. A successful exploit could allow the attacker to write a file that consumes most of the available disk space on the system, causing application functions to operate abnormally and leading to a DoS condition. This vulnerability affects Cisco IP Phone 8800 Series products running a SIP Software release prior to 12.5(1)SR1.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/04/2023
The vulnerability described in CVE-2019-1766 represents a critical denial of service weakness within the web-based management interface of Cisco IP Phone 8800 Series devices. This issue stems from insufficient input validation and file size restriction mechanisms within the SIP software implementation. The flaw specifically targets the system's handling of file operations, where the software fails to enforce limits on the maximum size of files that can be written to the device's storage medium. This design oversight creates a pathway for malicious actors to exploit the system's resource management capabilities, potentially leading to complete service disruption. The vulnerability impacts devices running SIP Software releases earlier than 12.5(1)SR1, making it particularly concerning given the widespread deployment of these telephony systems in enterprise environments.
The technical exploitation of this vulnerability follows a specific attack pattern that aligns with common remote code execution and resource exhaustion attack vectors. An authenticated attacker with valid administrator credentials can leverage this weakness by crafting and transmitting a specially formatted remote connection request to the affected system. This request triggers the system to process and store a file that grows beyond normal operational parameters, consuming excessive disk space. The implementation flaw occurs at the file system level where the software lacks proper bounds checking mechanisms for file size validation. According to CWE classification, this vulnerability maps to CWE-770, which addresses allocation of resources without proper limits or throttling, and CWE-400, which covers unspecified resource exhaustion conditions. The attack vector operates through the web interface management protocols, making it accessible to remote adversaries who can leverage existing administrative credentials to execute the exploit.
The operational impact of this vulnerability extends beyond simple service disruption to create significant business continuity risks for organizations relying on these communication systems. When the disk space becomes consumed, the affected Cisco IP Phone 8800 Series devices experience abnormal application behavior that can render them completely non-functional. The system may become unresponsive to legitimate calls, fail to register with the SIP server, or exhibit other erratic behavior that prevents normal telephony operations. This DoS condition can persist until manual intervention occurs, including system reboots, disk cleanup operations, or complete software reinstallation. The vulnerability particularly affects enterprise environments where phone systems are critical for business operations, potentially causing cascading effects throughout organizational communication networks. Organizations may face productivity losses, emergency response delays, and increased IT support overhead as they work to recover from such incidents.
Mitigation strategies for CVE-2019-1766 should prioritize immediate software updates to the affected Cisco IP Phone 8800 Series devices, specifically upgrading to SIP Software release 12.5(1)SR1 or later versions that contain the necessary patches. Network segmentation and access control measures should be implemented to limit administrative access to only trusted personnel, reducing the attack surface available to potential adversaries. Regular monitoring of system disk utilization and implementation of automated alerts for unusual resource consumption patterns can help detect exploitation attempts before they cause complete service disruption. Additionally, organizations should consider implementing network-based intrusion detection systems that can identify suspicious connection patterns associated with this specific vulnerability. The ATT&CK framework categorizes this vulnerability under T1499.004 for network denial of service and T1078.004 for valid accounts, highlighting the importance of account management and network security controls. Regular vulnerability assessments and security audits should be conducted to identify and remediate similar weaknesses in other networked devices within the organization's infrastructure.