CVE-2017-12230 in IOS XE
Summary
by MITRE
A vulnerability in the web-based user interface (web UI) of Cisco IOS XE 16.2 could allow an authenticated, remote attacker to elevate their privileges on an affected device. The vulnerability is due to incorrect default permission settings for new users who are created by using the web UI of the affected software. An attacker could exploit this vulnerability by using the web UI of the affected software to create a new user and then logging into the web UI as the newly created user. A successful exploit could allow the attacker to elevate their privileges on the affected device. This vulnerability affects Cisco devices that are running a vulnerable release Cisco IOS XE Software, if the HTTP Server feature is enabled for the device. The newly redesigned, web-based administration UI was introduced in the Denali 16.2 Release of Cisco IOS XE Software. This vulnerability does not affect the web-based administration UI in earlier releases of Cisco IOS XE Software. Cisco Bug IDs: CSCuy83062.
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Analysis
by VulDB Data Team • 01/14/2021
This vulnerability resides within the web-based user interface of Cisco IOS XE Software version 16.2, representing a critical privilege escalation flaw that exploits improper default permission configurations. The issue specifically affects devices running the Denali 16.2 release and later versions where the HTTP Server feature is enabled, creating a pathway for authenticated remote attackers to gain elevated system privileges. The vulnerability stems from insufficient access control mechanisms implemented during user creation processes through the web UI, allowing attackers to manipulate default permissions that should restrict new user accounts to standard privileges.
The technical exploitation occurs through the web UI's user management functionality, where attackers can create new user accounts with elevated permissions by leveraging the flawed default settings. This vulnerability operates under CWE-276, which addresses improper permissions for system resources, specifically targeting the privilege escalation vector within network device management interfaces. The flaw demonstrates a clear violation of the principle of least privilege, where newly created accounts are inadvertently granted administrative capabilities that should be restricted to authorized administrators only. Attackers can exploit this by simply logging into the web UI as the newly created user account, bypassing normal authentication and authorization controls that should prevent such privilege elevation.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to perform administrative functions such as modifying device configurations, accessing sensitive network data, and potentially compromising the entire network infrastructure. The vulnerability affects Cisco devices including routers and switches running vulnerable IOS XE software releases, making it particularly concerning for enterprise networks where these devices serve as critical infrastructure components. The attack vector is particularly dangerous because it requires only web UI access and authentication, eliminating the need for physical access or more sophisticated attack methods. This weakness creates a persistent threat that can be exploited by attackers with minimal privileges, potentially leading to complete network compromise and data breaches.
Mitigation strategies should focus on immediate software patching and configuration hardening measures. Organizations must upgrade to Cisco IOS XE Software releases that contain the fix for CSCuy83062, which addresses the default permission configuration issues in the web UI. Additionally, implementing network segmentation and access controls can limit exposure by restricting web UI access to trusted administrative networks only. Security monitoring should be enhanced to detect unusual user creation activities or privilege escalation attempts within the web UI. The vulnerability also highlights the importance of following the principle of least privilege in network device management, ensuring that default user accounts and newly created users are granted only necessary permissions. Organizations should also consider disabling the HTTP Server feature entirely if web UI access is not required, following the defense-in-depth approach recommended by cybersecurity frameworks such as NIST SP 800-53. This vulnerability serves as a reminder of the critical importance of secure configuration management and proper access control implementation in network infrastructure devices.