Releases

advisories

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CodiMD Unauthorised Image Access

This advisory details a missing authentication and access control vulnerability allowing an unauthenticated attacker to gain unauthorised access to image data uploaded to CodiMD. Due to the insecure random filename generation functionality in the underlying Formidable library, filenames for uploaded images could be determined and the likelihood of this issue being exploited was increased.


Slack Web Hook Message Injection Advisory

Slack integrations such as webhook APIs are often used to alert on user actions to internal teams. A vulnerability was noted when user supplied data containing a large amount of white space was included in a request to the Slack webhook API. By including enough white space in this data, the messages would be split and truncated. As a result, the malicious payload after the whitespace would appear as a standalone message from the Slack bot. An attacker could exploit this to forge messages containing Slack message markup to perform social engineering and other attacks if an integration, such as a website or other software, included unvalidated user input in the message to the Slack webhook.


Bypassing USBGuard on Linux

Configuring USBGuard without explicitly specifying vendor and product IDs allows an attacker to bypass some USB authorisation policies on Linux. A device may claim to belong to one USB class (e.g. say it’s a keyboard), but actually act as a network adapter, mass storage or other more exotic device. The Gnome desktop’s USB protection policies are vulnerable by default.


articles

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Bypassing WiFi Client Isolation

WiFi network client isolation is a security feature that prevents devices connected to the same network communicating directly with each other. This article shows how to bypass client isolation by manually crafting packets and injecting them into the air with a monitor mode wireless adapter, even with WPA2-PSK enabled. This allows an attacker to target other connected devices through bypassing the access point entirely, along with the client isolation security it enforces.


HTTP Really Isn't That Simple (and by extension Neither Is Your Outbound Web Filtering, Actually)

This article takes a close look at what stands in the way of filtering outbound HTTP to the wider web in a restricted server environment, shows how to evade typical filtering configuration using a relative of domain fronting, and presents some ideas for ways to plug this gap.


Making Mutual TLS Easier

TLS is good, arguably necessary, but managing PKI makes me feel bad. Is there no other way? This article will show how you can reap the benefits of mutual TLS quickly and easily without the mire of PKI.