matrix-js-sdk up to 19.6.x Message key exchange without entity authentication

Summaryinfo

A vulnerability identified as problematic has been detected in matrix-js-sdk up to 19.6.x. This vulnerability affects unknown code of the component Message Handler. The manipulation leads to key exchange without entity authentication. This vulnerability is traded as CVE-2022-39249. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in matrix-js-sdk up to 19.6.x. This issue affects some unknown functionality of the component Message Handler. The manipulation with an unknown input leads to a key exchange without entity authentication vulnerability. Using CWE to declare the problem leads to CWE-322. The product performs a key exchange with an actor without verifying the identity of that actor. Impacted is integrity. The summary by CVE is:

Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-js-sdk implementing a too permissive key forwarding strategy on the receiving end. Starting with version 19.7.0, the default policy for accepting key forwards has been made more strict in the matrix-js-sdk. matrix-js-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately, for example, by showing a warning for such messages. This attack requires coordination between a malicious homeserver and an attacker, and those who trust your homeservers do not need a workaround.

The weakness was shared 09/29/2022 as GHSA-6263-x97c-c4gg. The advisory is shared at github.com. The identification of this vulnerability is CVE-2022-39249 since 09/02/2022. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 208577 (CentOS 7 : thunderbird (RHSA-2022:7184)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 19.7.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch a587d7c36026fe1fcf93dfff63588abee359be76 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (208577). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• matrix-js-sdk

Version

• 19.0
• 19.1
• 19.2
• 19.3
• 19.4
• 19.5
• 19.6

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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