Impact
It was possible to craft an event such that it would leak part of a targeted message event from another bridged room. This required knowing an event ID to target.
Patches
Please upgrade to 1.0.1.
Workarounds
You can set the matrixHandler.eventCacheSize config value to 0 to workaround this bug. However, this may impact performance.
Credits
Discovered and reported by Val Lorentz.
For more information
If you have any questions or comments about this advisory email us at security@matrix.org.
Impact
A malicious Matrix server can use a foreign user's MXID in an OpenID exchange, allowing a bad actor to impersonate users when using the provisioning API.
Details
The library does not check that the servername part of the sub parameter (containing the user's claimed MXID) is the same as the servername we are talking to. A malicious actor could spin up a server on any given domain, respond with a sub parameter according to the user they want to act as and use the resulting token to perform provisioning requests.
Workarounds
Disable the provisioning API. If the bridge does not use the provisioning API, you are not vulnerable.
Impact
It is possible to craft a command with newlines which would not be properly parsed. This would mean you could pass a string of commands as a channel name, which would then be run by the IRC bridge bot.
Patches
Versions 1.0.1 and above are patched.
Workarounds
There are no robust workarounds to the bug. You can disable dynamic channels in the config to disable the most common execution method but others may exist. It is highly recommended to upgrade the bridge.
Credits
Discovered and reported by Val Lorentz.
For more information
If you have any questions or comments about this advisory email us at security@matrix.org.
matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel. The vulnerability has been patched in matrix-appservice-irc 0.35.0. As a workaround operators may disable dynamic channel joining via dynamicChannels.enabled to prevent users from joining new channels, which prevents any new channels being bridged outside of what is already bridged, and what is specified in the config.
matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. The Internet Relay Chat (IRC) protocol allows you to specify multiple modes in a single mode command. Due to a bug in the underlying matrix-org/node-irc library, affected versions of matrix-appservice-irc perform parsing of such modes incorrectly, potentially resulting in the wrong user being given permissions. Mode commands can only be executed by privileged users, so this can only be abused if an operator is tricked into running the command on behalf of an attacker. The vulnerability has been patched in matrix-appservice-irc 0.35.0. As a workaround users should refrain from entering mode commands suggested by untrusted users. Avoid using multiple modes in a single command.
matrix-appservice-irc is a Node.js IRC bridge for Matrix. The vulnerability in node-irc allows an attacker to manipulate a Matrix user into executing IRC commands by having them reply to a maliciously crafted message. The vulnerability has been patched in matrix-appservice-irc 0.33.2. Refrain from replying to messages from untrusted participants in IRC-bridged Matrix rooms. There are no known workarounds for this issue.