Overview
Multiple BGP implementations have been identified as vulnerable to specially crafted Path Attributes of a BGP UPDATE. Instead of ignoring invalid updates they reset the underlying TCP connection for the BGP session and de-peer the router.

This is undesirable because a session reset impacts not only routes with the BGP UPDATE but also the other valid routes exchanged over the session. RFC 7606 Introduction

Description
The Border Gateway Protocol (BGP, RFC 4271) is a widely used inter-Autonomous System routing protocol. BGP communication among peer routers is critical to the stable operation of the Internet. A number of known BGP security issues were addressed in RFC 7606 Revised Error Handling for BGP UPDATE Messages in 2015.
Recent reports indicate that multiple BGP implementations do not properly handle specially crafted Path Attributes in the BGP UPDATE messages. An attacker with a valid, configured BGP session could inject a specially crafted packet into an existing BGP session or the underlying TCP session (179/tcp). A vulnerable BGP implementation could drop sessions when processing crafted UPDATE messages. A persistent attack could lead to routing instability (route flapping).
This vulnerability was first announced as affecting OpenBSD based routers. Further investigation indicates that other vendors are affected by the same or similar issues. Please see the Systems Affected section below.
Here are the CVE IDs that were reserved by the reporter for different vendors that were tested:

CVE-2023-4481 (Juniper)
CVE-2023-38802 (FRR)
CVE-2023-38283 (OpenBGPd)
CVE-2023-40457 (EXOS)

Impact
A remote attacker could publish a BGP UPDATE with a crafted set of Path Attributes, causing vulnerable routers to de-peer from any link from which such an update were received. Unaffected routers might also pass the crafted updates across the network, potentially leading to the update arriving at an affected router from multiple sources, causing multiple links to fail.
Solution
The CERT/CC is currently unaware of a practical solutions for every vendor but some of the vendors allow you to change the response to errors in BGP path updates. Networks using appliances from Juniper and Nokia can mitigate this behavior by enabling:
(Juniper)
set protocols bgp bgp-error-tolerance
(Nokia)
[router bgp group]
error-handling update-fault-tolerance
Acknowledgements
Thanks to the reporter Ben Cartwright-Cox. This document was written by Timur Snoke.

Overview
An authentication bypass vulnerability exists in the N300 Wireless N VDSL2 Modem Router manufactured by Tenda. This vulnerability allows a remote, unauthenticated user to access sensitive information.
Description
CVE-2023-4498 is an authentication bypass vulnerability that enables an unauthenticated attacker who has access to the web console, either locally or remotely, to access resources that would normally be protected. The attacker can construct a web request that includes a white-listed keyword in the path, causing the URL to be served directly (rather than blocked or challenged with an authentication prompt).
Impact
Successful exploitation of this vulnerability could grant the attacker access to pages that would otherwise require authentication. An unauthenticated attacker could thereby gain access to sensitive information, such as the Administrative password, which could be used to launch additional attacks.
Solution
There is no known solution to the vulnerability. Always update your router to the latest available firmware version. Disabling both the remote (WAN-side) administration services and the web interface on the WAN on any SoHo router is also recommended.
Acknowledgements
Thanks to the reporter from the Spike Reply Cybersecurity Team. This document was written by Timur Snoke.

Overview
Groupnotes Inc. Videostream Mac client installs a LaunchDaemon that runs with root privileges. The daemon is vulnerable to a race condition that allows for arbitrary file writes. A low privileged attacker can escalate privileges to root on affected systems.
Description
Every five hours the Videostream LaunchDaemon runs with root privileges to check for updates. During the download, it’s possible to replace the update file as any user with a crafted tar archive. The LaunchDaemon process will extract the archive and replace any requested file on the system.
Impact
An attacker with low privilege access can overwrite arbitrary files on the affected system. This can be leveraged to escalate privileges to control the root account.
Solution
The CERT/CC is currently unaware of a practical solution to this problem.
Acknowledgements
Thank you to Dan Revah for reporting this issue.
This document was written by Kevin Stephens.