CVE-2017-6781 in Policy Suite CPS
Summary
by MITRE
A vulnerability in the management of shell user accounts for Cisco Policy Suite (CPS) Software for CPS appliances could allow an authenticated, local attacker to gain elevated privileges on an affected system. The affected privilege level is not at the root level. The vulnerability is due to incorrect role-based access control (RBAC) for shell user accounts. An attacker could exploit this vulnerability by authenticating to an affected appliance and providing crafted user input via the CLI. A successful exploit could allow the attacker to acquire a higher privilege level than should have been granted. To exploit this vulnerability, the attacker must log in to the appliance with valid credentials. Cisco Bug IDs: CSCve37724. Known Affected Releases: 9.0.0, 9.1.0, 10.0.0, 11.0.0, 12.0.0.
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Analysis
by VulDB Data Team • 01/09/2021
The vulnerability identified as CVE-2017-6781 represents a critical privilege escalation flaw within Cisco Policy Suite software that specifically targets the management of shell user accounts on CPS appliances. This weakness stems from inadequate implementation of role-based access control mechanisms that govern how authenticated users interact with the command-line interface of affected systems. The vulnerability affects multiple major releases including versions 9.0.0 through 12.0.0, indicating a widespread issue that spans several generations of the software platform. The flaw operates at the shell level where users with valid credentials can manipulate their access privileges through crafted input sequences, bypassing the intended security boundaries that should restrict user capabilities based on their assigned roles.
The technical execution of this vulnerability relies on the manipulation of shell user accounts through the command-line interface where an authenticated attacker can exploit the improper RBAC implementation to escalate their privileges beyond what their account should permit. This particular weakness falls under the category of CWE-284 - Improper Access Control, which specifically addresses situations where the system fails to properly enforce access restrictions for different user roles. The vulnerability demonstrates a classic case of privilege escalation where the system fails to properly validate the privilege level of authenticated users, allowing them to execute commands that should be restricted to higher-privilege accounts. The attack vector requires local authentication, meaning that an attacker must first obtain valid credentials to the system, but once authenticated, they can leverage this flaw to gain elevated access.
The operational impact of this vulnerability extends beyond simple unauthorized access as it enables attackers to potentially compromise the entire appliance by acquiring elevated privileges that allow them to modify system configurations, access sensitive data, or even disable security features. While the privilege level achieved is not root-level, the elevation still provides significant control over the affected system, potentially allowing attackers to establish persistent access, modify critical policies, or interfere with the appliance's primary function of enforcing network security policies. This vulnerability directly impacts the integrity and availability of the security infrastructure, as an attacker who successfully exploits this flaw could undermine the very security controls that the appliance is designed to provide. The attack requires minimal prerequisites beyond valid authentication credentials, making it particularly dangerous in environments where credential exposure or insider threats are concerns.
Organizations affected by this vulnerability should immediately implement mitigations including applying the latest security patches from Cisco, reviewing and strengthening authentication mechanisms, and monitoring for suspicious privilege escalation attempts within system logs. The implementation of additional access controls such as mandatory access control policies and regular privilege audits can help detect and prevent exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, specifically targeting the T1068 - Exploitation for Privilege Escalation and T1078 - Valid Accounts categories. The affected systems should also undergo comprehensive security assessments to identify any potential post-exploitation activities and ensure that no unauthorized access has occurred. Network segmentation and limiting local access to these appliances can further reduce the attack surface and provide additional layers of defense against exploitation attempts.