CVE-2017-8230 in IPM-721S
Summary
by MITRE
On Amcrest IPM-721S V2.420.AC00.16.R.20160909 devices, the users on the device are divided into 2 groups "admin" and "user". However, as a part of security analysis it was identified that a low privileged user who belongs to the "user" group and who has access to login in to the web administrative interface of the device can add a new administrative user to the interface using HTTP APIs provided by the device and perform all the actions as an administrative user by using that account. If the firmware version V2.420.AC00.16.R 9/9/2016 is dissected using binwalk tool, one obtains a _user-x.squashfs.img.extracted archive which contains the filesystem set up on the device that many of the binaries in the /usr folder. The binary "sonia" is the one that has the vulnerable functions that performs the various action described in HTTP APIs. If one opens this binary in IDA-pro one will notice that this follows a ARM little endian format. The function at address 0x00429084 in IDA pro is the one that processes the HTTP API request for "addUser" action. If one traces the calls to this function, it can be clearly seen that the function sub_ 41F38C at address 0x0041F588 parses the call received from the browser and passes it to the "addUser" function without any authorization check.
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Analysis
by VulDB Data Team • 10/17/2023
The vulnerability described in CVE-2017-8230 represents a critical privilege escalation flaw in Amcrest IPM-721S security cameras running firmware version V2.420.AC00.16.R.20160909. This issue fundamentally undermines the device's access control mechanisms by allowing unauthenticated low-privilege users to escalate their privileges through legitimate administrative APIs. The device implements a standard user group hierarchy with distinct "admin" and "user" roles, yet the security model fails at the API level where proper authentication and authorization checks are absent. This vulnerability directly maps to CWE-284 which describes improper access control, and aligns with ATT&CK technique T1068 for privilege escalation through local exploitation.
The technical implementation of this vulnerability resides within the embedded firmware's binary components, specifically the "sonia" binary extracted from the _user-x.squashfs.img.archive using tools like binwalk. This binary operates in ARM little endian format and contains the core functionality for handling HTTP API requests. The vulnerable function located at address 0x00429084 serves as the primary entry point for user creation operations, while the supporting function sub_41F38C at address 0x0041F588 acts as the parsing layer that processes incoming HTTP requests without performing any authorization validation. The absence of proper input sanitization and privilege verification creates a direct path for privilege escalation attacks.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it enables attackers to completely compromise the device's administrative capabilities. Once a user gains access to the web interface, they can create new administrative accounts and perform any action that an administrator could execute, including modifying device settings, accessing video feeds, changing user permissions, and potentially using the device as a pivot point for network reconnaissance. This represents a complete breakdown of the principle of least privilege and allows attackers to maintain persistent access to the network infrastructure. The vulnerability affects the device's web administration interface and HTTP API endpoints, making it exploitable through standard web browser-based attacks.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. Device administrators should immediately update to the latest firmware versions that contain proper authentication checks and authorization controls. Network segmentation should be implemented to isolate these devices from critical network segments, and access controls should be tightened to limit administrative access to authorized personnel only. Regular security audits of embedded systems should be conducted to identify similar privilege escalation vulnerabilities in other networked devices. The vulnerability demonstrates the importance of implementing proper input validation and authorization checks at all levels of embedded system development, aligning with security best practices outlined in NIST SP 800-144 and OWASP IoT Security guidelines. Additionally, network monitoring should be enhanced to detect unusual user creation activities and unauthorized administrative access patterns that may indicate exploitation attempts.