CVE-2017-9392 in VeraEdge
Summary
by MITRE
An issue was discovered on Vera VeraEdge 1.7.19 and Veralite 1.7.481 devices. The device provides UPnP services that are available on port 3480 and can also be accessed via port 80 using the url "/port_3480". It seems that the UPnP services provide "request_image" as one of the service actions for a normal user to retrieve an image from a camera that is controlled by the controller. It seems that the "res" (resolution) parameter passed in the query string is not sanitized and is stored on the stack which allows an attacker to overflow the buffer. The function "LU::Generic_IP_Camera_Manager::REQ_Image" is activated when the lu_request_image is passed as the "id" parameter in the query string. This function then calls "LU::Generic_IP_Camera_Manager::GetUrlFromArguments". This function retrieves all the parameters passed in the query string including "res" and then uses the value passed in it to fill up buffer using the sprintf function. However, the function in this case lacks a simple length check and as a result an attacker who is able to send more than 184 characters can easily overflow the values stored on the stack including the $RA value and thus execute code on the device.
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Analysis
by VulDB Data Team • 10/05/2023
The vulnerability identified in CVE-2017-9392 affects VeraEdge 1.7.19 and Veralite 1.7.481 devices, representing a critical buffer overflow flaw within the Universal Plug and Play (UPnP) implementation. These devices expose UPnP services on port 3480 and additionally provide access via port 80 through the URL path "/port_3480", creating multiple attack vectors for exploitation. The specific vulnerability manifests in the UPnP service's handling of image requests from IP cameras, where the "request_image" service action allows users to retrieve camera images through the controller system.
The technical flaw resides in the LU::Generic_IP_Camera_Manager::REQ_Image function which processes the lu_request_image parameter in query strings. When this function is invoked, it triggers the LU::Generic_IP_Camera_Manager::GetUrlFromArguments function that parses all incoming parameters including the critical "res" (resolution) parameter. The vulnerability stems from insufficient input validation where the "res" parameter value is directly used in a sprintf function without proper length checking. This design flaw creates a classic stack-based buffer overflow condition, as the function fails to verify that the input data does not exceed the allocated buffer space of 184 characters.
The operational impact of this vulnerability extends beyond simple denial of service, as it enables remote code execution on the affected devices. Attackers can exploit this buffer overflow by sending maliciously crafted payloads exceeding 184 characters, which overwrite the stack memory including the return address ($RA) and potentially other critical stack variables. This allows malicious actors to redirect program execution flow and execute arbitrary code with the privileges of the UPnP service process, effectively compromising the entire device. The vulnerability affects devices running on embedded operating systems where memory management is more constrained, making exploitation more reliable.
This vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is categorized under the Common Weakness Enumeration framework as a fundamental memory safety issue. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under T1059.007 Command and Scripting Interpreter: Python, as exploitation typically requires crafting specific network requests to manipulate the vulnerable service. The attack surface is particularly concerning given that UPnP services are designed to be accessible from external networks, and the vulnerable port 3480 is commonly exposed to internet-connected devices. Organizations should implement immediate network segmentation to isolate affected devices, disable unnecessary UPnP services where possible, and apply firmware updates from Vera to remediate the vulnerability. Additionally, network monitoring should be enhanced to detect anomalous UPnP traffic patterns that may indicate exploitation attempts.