CVE-2017-8333 in Almond
Summary
by MITRE
An issue was discovered on Securifi Almond, Almond+, and Almond 2015 devices with firmware AL-R096. The device provides a user with the capability of adding new routes to the device. It seems that the POST parameters passed in this request to set up routes on the device can be set in such a way that would result in passing commands to a "popen" API in the function and thus result in command injection on the device. If the firmware version AL-R096 is dissected using binwalk tool, we obtain a cpio-root archive which contains the filesystem set up on the device that contains all the binaries. The binary "goahead" is the one that has the vulnerable function that receives the values sent by the POST request. If we open this binary in IDA-pro we will notice that this follows a MIPS little endian format. The function sub_00420F38 in IDA pro is identified to be receiving the values sent in the POST request and the value set in POST parameter "dest" is extracted at address 0x00420FC4. The POST parameter "dest is concatenated in a route add command and this is passed to a "popen" function at address 0x00421220. This allows an attacker to provide the payload of his/her choice and finally take control of the device.
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Analysis
by VulDB Data Team • 10/06/2023
The vulnerability identified in CVE-2017-8333 affects Securifi Almond, Almond+, and Almond 2015 devices running firmware version AL-R096, representing a critical command injection flaw that compromises the entire device ecosystem. This vulnerability stems from improper input validation within the web application interface that handles routing configuration requests. The affected device employs a web server implementation using the goahead web server framework, where user-supplied data from HTTP POST requests is directly processed without adequate sanitization or validation mechanisms.
The technical exploitation occurs through the vulnerable function sub_00420F38 within the goahead binary, which processes routing configuration parameters submitted via HTTP POST requests. Specifically, the POST parameter "dest" is extracted at memory address 0x00420FC4 and subsequently concatenated into a route addition command string. This constructed command string is then passed to the popen API function at address 0x00421220, creating a direct pathway for arbitrary command execution. The vulnerability manifests as a classic command injection flaw where attacker-controlled input bypasses all security controls and directly executes system commands with the privileges of the web server process.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete device compromise and potential network infiltration. An attacker can leverage this vulnerability to execute arbitrary commands on the device, potentially leading to persistent backdoor installation, data exfiltration, or use of the compromised device as a pivot point for attacking other networked systems. The MIPS little endian architecture of the embedded device adds complexity to exploitation but does not mitigate the fundamental vulnerability, as the command injection occurs at the application layer regardless of the underlying processor architecture. The vulnerability affects devices that are typically deployed in home and small office environments, making them attractive targets for attackers seeking to establish persistent access points within local networks.
Security implications of CVE-2017-8333 align with CWE-77 and CWE-78 categories, specifically addressing command injection vulnerabilities where user input is improperly handled in system command execution contexts. The vulnerability demonstrates poor input validation practices and inadequate sanitization of user-supplied data, creating an attack surface that allows arbitrary code execution. From an ATT&CK framework perspective, this vulnerability maps to techniques involving command and script execution, privilege escalation, and persistence mechanisms, enabling attackers to establish long-term control over affected devices. The exploitation requires only a web browser and network access to the device, making it particularly dangerous as it can be exploited remotely without physical access or specialized tools. Mitigation strategies should include firmware updates from the vendor, network segmentation to isolate affected devices, and implementation of network monitoring to detect suspicious command execution patterns. The vulnerability underscores the importance of input validation and secure coding practices in embedded systems, particularly those handling user-supplied data in system command contexts.