CVE-2011-1602 in Skinny Client Control Protocol Software
Summary
by MITRE
The su utility on Cisco Unified IP Phones 7900 devices (aka TNP phones) with software before 9.0.3 allows local users to gain privileges via unspecified vectors, aka Bug ID CSCtf07426.
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Analysis
by VulDB Data Team • 11/08/2021
The vulnerability identified as CVE-2011-1602 affects Cisco Unified IP Phones 7900 series devices, commonly known as TNP phones, which operate on software versions prior to 9.0.3. This represents a critical privilege escalation flaw within the system's core utility functions, specifically targeting the su command that is responsible for switching user identities and granting administrative privileges. The vulnerability exists in the local security mechanisms of these telephony devices, creating a potential pathway for malicious actors with local access to escalate their privileges and gain unauthorized administrative control over the affected systems. The issue stems from insufficient input validation and privilege handling within the su utility implementation, allowing attackers to exploit unspecified vectors that bypass normal authentication and authorization checks.
The technical flaw manifests through improper handling of privilege elevation requests within the su utility, which is a fundamental component of Unix-like operating systems that allows users to switch to different user accounts with potentially elevated privileges. In the context of these Cisco IP phones, the vulnerability enables local users to manipulate the utility in ways that should not be permitted under normal security protocols. The unspecified vectors suggest that the flaw could be exploited through multiple methods including but not limited to malformed input parameters, improper access control checks, or inadequate privilege validation routines. This type of vulnerability typically falls under CWE-264, which addresses permissions, privileges, and access controls, and represents a classic case of insufficient privilege checking that allows unauthorized privilege escalation.
The operational impact of this vulnerability is substantial for organizations relying on Cisco Unified IP Phones for their communication infrastructure. Local attackers who can gain access to these devices can potentially execute arbitrary commands with administrative privileges, leading to complete system compromise. This could result in unauthorized access to sensitive communication data, modification of phone configurations, interception of voice communications, and potential use as a pivot point for further attacks within the network. The vulnerability is particularly concerning because it affects devices that are often deployed in sensitive environments such as corporate offices, healthcare facilities, and government buildings where communication security is paramount. Attackers could leverage this privilege escalation to install backdoors, modify phone directories, or disrupt critical communication services, making it a significant risk to business continuity and information security.
Organizations should implement immediate mitigations including upgrading to Cisco software version 9.0.3 or later, which contains the necessary patches to address this vulnerability. Network segmentation and access control measures should be strengthened to limit local access to these devices, while regular security audits should be conducted to identify any potential exploitation attempts. The vulnerability aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation, and organizations should consider implementing monitoring solutions that can detect anomalous privilege escalation activities. Additionally, implementing principle of least privilege for local access, disabling unnecessary services, and maintaining detailed logs of system access and privilege changes are recommended defensive measures. The Cisco Security Advisory for this vulnerability should be reviewed and implemented as part of the overall security posture improvement strategy, particularly focusing on the specific patch management procedures for telephony infrastructure devices.