Overview
A stack overflow vulnerability has been discovered within the libexpat open source library. When parsing XML documents with deeply nested entity references, libexpat can recurse indefinitely. This can result in exhaustion of stack space and a crash. An attacker can weaponize this to either perform denial of service (DoS) attacks or memory corruption attacks, based on the libexpat environment and library usage.
Description
libexpat is an Open Source XML parsing library. It is a stream oriented XML parsing library written in the C programming language. It can be used in particular with large files difficult for processing in RAM. A vulnerability has been discovered, tracked as CVE-2024-8176. The vulnerability description can be observed below.
CVE-2024-8176
A stack overflow vulnerability exists in the libexpat library due to the way it handles recursive entity expansion in XML documents. When parsing an XML document with deeply nested entity references, libexpat can be forced to recurse indefinitely, exhausting the stack space and causing a crash. This issue could lead to denial of service (DoS) or, in some cases, exploitable memory corruption, depending on the environment and library usage.
Impact
An attacker with access to software that uses libexpat could provide a XML document to the program and cause a DoS attack or memory corruption attack. libexpat is used in a variety of different software, and by various companies.
Solution
A patch for the vulnerability has been provided in version 2.7.0 of libexpat. Groups that use libexpat can verify their patch using the POCs provided here: https://github.com/libexpat/libexpat/issues/893#payload_generators
Acknowledgements
This vulnerability was reported to us by the maintainer of the project, Sebastian Pipping, to increase awareness. The vulnerability was originally discovered by Jann Horn of Googles Project Zero. Vendors who wish to join the discussion within VINCE can do so here: https://www.kb.cert.org/vince/. This document was written by Christopher Cullen.

Overview
The Radware Cloud Web Application Firewall is vulnerable to filter bypass by multiple means. The first is via specially crafted HTTP request and the second being insufficient validation of user-supplied input when processing a special character. An attacker with knowledge of these vulnerabilities can perform additional attacks without interference from the firewall.
Description
The Radware Cloud Web Application Firewall can be bypassed by means of a crafted HTTP request. If random data is included in the HTTP request body with a HTTP GET method, WAF protections may be bypassed. It should be noted that this evasion is only possible for those requests that use the HTTP GET method.
Another way the Radware Cloud WAF can be bypassed is if an attacker adds a special character to the request. The firewall fails to filter these requests and allows for various payloads to reach the underlying web application.
Impact
An attacker with knowledge of these vulnerabilities can bypass filtering. This allows malicious inputs to reach the underlying web application.
Solution
The vulnerabilities appear to be fixed, however Radware has not acknowledged the reporter’s findings when they were initially disclosed.
Acknowledgements
Thanks to Oriol Gegundez for reporting this issue. This document was written by Kevin Stephens and Ben Koo.

Overview
Digigrams PYKO-OUT audio-over-IP (AoIP) product is used for audio decoding and intended for various uses such as paging, background music, live announcements and others. It has hardware compatibility with two analog mono outputs and a USB port for storing local playlists. The product does not require a password by default, and when opened to the Internet, can allow attackers access to the device, where they can then pivot to attacking adjacent connected devices or compromise the device’s functionality.
Description
Digigram is an audio-based hardware and software vendor, providing various products including sound cards, AoIP gateways, and speaker-related support software. Digigram sells a PYKO-OUT audio-over-IP product that is used for audio decoding and intended for various uses such as paging, background music, and live announcements.
A vulnerability has been discovered within the web-server component of the PYKO-OUT AoIP, where the default configuration does not require any login information or password. This web server spawns on 192.168.0.100 by default. The lack of log-in credentials allows any attacker who discovers the vulnerable IP address of the device to connect and manipulate it, without any authentication or authorization.
An attacker who gains access to the device can access its configuration, control audio outputs and inputs, and potentially pivot to other connected devices, whether this be through network connections, or by placing malicious files in a connected USB device.
Impact
An attacker with access to a vulnerable device can access the devices configuration, control audio-over-IP data streams managed by the device, and pivot to other network and physical connected devices, such as through a connected USB thumb drive.
Solution
Digigram has marked this product as EOL and will not be providing a patch to change the default configuration. Users can alter the password settings within the web server UI and force attempted connections to provide a password. Additionally, the product is no longer being sold by Digigram.
Acknowledgements
Thanks to the reporter, Souvik Kandar. Additional thanks to CERT-FR. This document was written by Christopher Cullen.