CVE-2022-39255: Matrix iOS SDK vulnerable ton Olm/Megolm protocol confusion
First published: Wed Sep 28 2022(Updated: )
Matrix iOS SDK allows developers to build iOS apps compatible with Matrix. Prior to version 0.23.19, an attacker cooperating with a malicious homeserver can construct messages that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. matrix-ios-sdk version 0.23.19 has been modified to only accept Olm-encrypted to-device messages. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround. To avoid malicious backup attacks, one should not verify one's new logins using emoji/QR verifications methods until patched.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Matrix Software Development Kit | <0.23.19 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://github.com/matrix-org/matrix-ios-sdk/commit/5ca86c328a5faaab429c240551cb9ca8f0f6262c
- https://github.com/matrix-org/matrix-ios-sdk/releases/tag/v0.23.19
- https://github.com/matrix-org/matrix-ios-sdk/security/advisories/GHSA-hw6g-j8v6-9hcm
- https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients
Frequently Asked Questions
What is CVE-2022-39255?
CVE-2022-39255 is a vulnerability in the Matrix iOS SDK that allows an attacker cooperating with a malicious homeserver to construct messages that appear to have come from another person without any indication.
How severe is CVE-2022-39255?
CVE-2022-39255 has a severity keyword of high and a severity value of 7.5.
Which version of the Matrix iOS SDK is affected by CVE-2022-39255?
Versions of the Matrix iOS SDK prior to 0.23.19 are affected by CVE-2022-39255.
How can an attacker exploit CVE-2022-39255?
An attacker cooperating with a malicious homeserver can exploit CVE-2022-39255 by constructing messages that appear to have come from another person without any indication.
How can I fix CVE-2022-39255?
To fix CVE-2022-39255, update to version 0.23.19 or later of the Matrix iOS SDK.
- collector/nvd-index
- agent/references
- agent/weakness
- agent/type
- agent/softwarecombine
- collector/mitre-cve
- source/MITRE
- agent/severity
- agent/title
- agent/remedy
- agent/last-modified-date
- agent/author
- agent/tags
- agent/description
- agent/first-publish-date
- agent/event
- vendor/matrix
- canonical/matrix software development kit