matrix-android-sdk2 up to 1.5.0 Message key exchange without entity authentication

Summaryinfo

A vulnerability described as critical has been identified in matrix-android-sdk2 up to 1.5.0. The affected element is an unknown function of the component Message Handler. Such manipulation leads to key exchange without entity authentication. This vulnerability is uniquely identified as CVE-2022-39246. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in matrix-android-sdk2 up to 1.5.0 and classified as critical. Affected by this issue is an unknown code block 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. CVE summarizes:

matrix-android-sdk2 is the Matrix SDK for Android. Prior to version 1.5.1, 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 key forwarding strategy implemented in the matrix-android-sdk2 that is too permissive. Starting with version 1.5.1, the default policy for accepting key forwards has been made more strict in the matrix-android-sdk2. The matrix-android-sdk2 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). As a workaroubnd, current users of the SDK can disable key forwarding in their forks using `CryptoService#enableKeyGossiping(enable: Boolean)`.

The weakness was disclosed 09/29/2022 as GHSA-2pvj-p485-cp3m. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2022-39246 since 09/02/2022. There are neither technical details nor an exploit publicly available.

Upgrading to version 1.5.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 77df720a238d17308deab83ecaa37f7a4740a17e 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.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• matrix-android-sdk2

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5.0

License

• open-source

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CPE 2.2info

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Once again VulDB remains the best source for vulnerability data.

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