CVE-2017-8227 in IPM-721S
Summary
by MITRE
Amcrest IPM-721S V2.420.AC00.16.R.20160909 devices have a timeout policy to wait for 5 minutes in case 30 incorrect password attempts are detected using the Web and HTTP API interface provided by the device. However, if the same brute force attempt is performed using the ONVIF specification (which is supported by the same binary) then there is no account lockout or timeout executed. This can allow an attacker to circumvent the account protection mechanism and brute force the credentials. 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 function that performs the credential check in the binary for the ONVIF specification. If one opens this binary in IDA-pro one will notice that this follows a ARM little endian format. The function at address 00671618 in IDA pro is parses the WSSE security token header. The sub_ 603D8 then performs the authentication check and if it is incorrect passes to the function sub_59F4C which prints the value "Sender not authorized."
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Analysis
by VulDB Data Team • 10/17/2023
The vulnerability described in CVE-2017-8227 represents a critical authentication bypass issue affecting Amcrest IPM-721S security cameras running firmware version V2.420.AC00.16.R.20160909. This flaw stems from an inconsistent implementation of account lockout mechanisms across different communication protocols supported by the device. The camera implements a 5-minute timeout policy for web and HTTP API interfaces after 30 failed authentication attempts, effectively protecting against brute force attacks through these channels. However, the same protection mechanism fails to apply when attackers utilize the ONVIF protocol, which shares the same underlying binary codebase and filesystem structure. This protocol-specific inconsistency creates a significant security gap that allows unauthorized credential guessing attempts to proceed without restriction.
The technical implementation of this vulnerability resides within the sonia binary extracted from the device's filesystem, specifically in the ARM little endian formatted executable structure. The vulnerable function at address 00671618 in IDA Pro performs WSSE security token header parsing, with subsequent authentication checks handled by sub_603D8 function. When authentication fails, the code path directs to sub_59F4C function which outputs the "Sender not authorized" message, but crucially lacks any account lockout or rate limiting mechanisms that would normally prevent repeated authentication attempts. This architectural oversight demonstrates a classic security flaw where different code paths within the same binary implement inconsistent access control policies, creating an exploitable attack surface that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables prolonged brute force attacks that can systematically compromise device access. Attackers can leverage the ONVIF interface to perform unlimited authentication attempts without triggering the protective timeout mechanisms, potentially leading to complete device compromise and unauthorized surveillance access. The vulnerability affects the device's overall security posture by undermining its authentication framework and creating a persistent attack vector that remains undetected by standard security monitoring systems. This flaw particularly impacts enterprise and industrial security deployments where camera devices are critical components of surveillance infrastructure.
Security mitigations for this vulnerability should focus on implementing consistent authentication policies across all supported protocols, ensuring that account lockout mechanisms function uniformly regardless of the communication interface used. Device manufacturers should conduct comprehensive security audits of their firmware to identify similar protocol-specific inconsistencies in authentication handling. Network segmentation and access control measures can provide temporary compensating controls by limiting direct access to vulnerable ONVIF interfaces, while regular firmware updates addressing the underlying code implementation are essential. This vulnerability aligns with CWE-305 authentication bypass weaknesses and maps to ATT&CK techniques involving credential access and privilege escalation through brute force methods, highlighting the importance of protocol-agnostic security controls in embedded device security architectures.