On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed: A vulnerability in the DMG file parser of ClamAV versions 1.0.0 and earlier, 0.105.1 and earlier, and 0.103.7 and earlier could allow an unauthenticated, remote attacker to access sensitive information on an affected device. This vulnerability is due to enabling XML entity substitution that may result in XML external entity injection. An attacker could exploit this vulnerability by submitting a crafted DMG file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to leak bytes from any file that may be read by the ClamAV scanning process.
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 |
|---|---|---|---|
| Secure_endpoint | Cisco | * | 1.20.2 (excluding) |
| Secure_endpoint | Cisco | * | 1.21.1 (excluding) |
| Secure_endpoint | Cisco | * | 7.5.9 (excluding) |
| Secure_endpoint | Cisco | 8.0.1.21160 (including) | 8.1.5 (excluding) |
| Secure_endpoint_private_cloud | Cisco | * | 3.6.0 (excluding) |
| Clamav | Ubuntu | bionic | * |
| Clamav | Ubuntu | devel | * |
| Clamav | Ubuntu | esm-infra/xenial | * |
| Clamav | Ubuntu | focal | * |
| Clamav | Ubuntu | jammy | * |
| Clamav | Ubuntu | kinetic | * |
| Clamav | Ubuntu | lunar | * |
| Clamav | Ubuntu | trusty | * |
| Clamav | Ubuntu | trusty/esm | * |
| Clamav | Ubuntu | xenial | * |
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.