Malicious Matrix homeserver can leak truncated message content of messages it shouldn't have access to

matrix-appservice-irc is a Node.js IRC bridge for the Matrix messaging protocol. The fix for GHSA-wm4w-7h2q-3pf7 / CVE-2024-32000 included in matrix-appservice-irc 2.0.0 relied on the Matrix homeserver-provided timestamp to determine whether a user has access to the event they're replying to when determining whether or not to include a truncated version of the original event in the IRC message. Since this value is controlled by external entities, a malicious Matrix homeserver joined to a room in which a matrix-appservice-irc bridge instance (before version 2.0.1) is present can fabricate the timestamp with the intent of tricking the bridge into leaking room messages the homeserver should not have access to. matrix-appservice-irc 2.0.1 drops the reliance on `origin_server_ts` when determining whether or not an event should be visible to a user, instead tracking the event timestamps internally. As a workaround, it's possible to limit the amount of information leaked by setting a reply template that doesn't contain the original message.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

不充分权限或特权的处理不恰当

matrix-appservice-irc 安全漏洞

matrix-appservice-irc是Matrix的一款网桥。这个网桥会将所有 IRC 消息传递给 Matrix，并将所有 Matrix 消息传递给 IRC。 matrix-appservice-irc 2.0.0之前版本存在安全漏洞，该漏洞源于恶意服务器可以伪造时间戳，意图诱骗桥接器泄露不应访问的消息。

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