Vulnerability · Published Sep 28, 2022 · Assigned by GitHub_M
CVE-2022-39246matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions
High 7.5
In plain English
A high-severity improper authentication in matrix-android-sdk2 from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 59% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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)`.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.matrix.android:matrix-android-sdk2 | 1.5.1 | GHSA-2pvj-p485-cp3m |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| matrix-org | matrix-android-sdk2 | < 1.5.1 |
Weakness: CWE-322, CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- https://github.com/matrix-org/matrix-spec-proposals/pull/3061 x_refsource_MISC
- https://github.com/matrix-org/matrix-android-sdk2/security/advisories/GHSA-2pvj-p485-cp3m x_refsource_CONFIRM
- https://github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f7a4740a17e x_refsource_MISC
- https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.5.1 x_refsource_MISC