A vulnerability was found in zwczou WeChat SDK Python 0.3.0 and classified as critical. This issue affects the function validate/to_xml. The manipulation leads to xml external entity reference. The attack may be initiated remotely. Upgrading to version 0.5.5 is able to address this issue. The patch is named e54abadc777715b6dcb545c13214d1dea63df6c9. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-223403.
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Wechat_sdk_python | Wechat_sdk_python_project | * | 0.5.5 (excluding) |
XML documents optionally contain a Document Type Definition (DTD), which, among other features, enables the definition of XML entities. It is possible to define an entity by providing a substitution string in the form of a URI. The XML parser can access the contents of this URI and embed these contents back into the XML document for further processing. By submitting an XML file that defines an external entity with a file:// URI, an attacker can cause the processing application to read the contents of a local file. For example, a URI such as “file:///c:/winnt/win.ini” designates (in Windows) the file C:\Winnt\win.ini, or file:///etc/passwd designates the password file in Unix-based systems. Using URIs with other schemes such as http://, the attacker can force the application to make outgoing requests to servers that the attacker cannot reach directly, which can be used to bypass firewall restrictions or hide the source of attacks such as port scanning. Once the content of the URI is read, it is fed back into the application that is processing the XML. This application may echo back the data (e.g. in an error message), thereby exposing the file contents.