{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/52264?format=json","vulnerability_id":"VCID-vx5q-mbn5-8kcf","summary":"matrix-android-sdk2 vulnerable to Olm/Megolm protocol confusion\n### Impact\nAn 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. \n\nAdditionally, 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. matrix-android-sdk2 would then additionally sign such a key backup with its device key, spilling trust over to other devices trusting the matrix-android-sdk2 device.\n\nThese attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm.\n\n### Patches\n\nmatrix-android-sdk2 has been modified to only accept Olm-encrypted to-device messages and to stop signing backups on a successful decryption.\n\nOut of caution, several other checks have been audited or added:\n- Cleartext `m.room_key`, `m.forwarded_room_key` and `m.secret.send` to_device messages are discarded.\n- Secrets received from untrusted devices are discarded.\n- Key backups are only usable if they have a valid signature from a trusted device (no more local trust, or trust-on-decrypt).\n- The origin of a to-device message should only be determined by observing the Olm session which managed to decrypt the message, and not by using claimed sender_key, user_id, or any other fields controllable by the homeserver.\n\n\n### Workarounds\n\nAs this attack requires coordination between a malicious home server and an attacker, if you trust your home server no particular workaround is needed.  Notice that the backup spoofing attack is a particularly sophisticated targeted attack.\n\nWe are not aware of this attack being used in the wild, though specifying a false positive-free way of noticing malicious key backups key is challenging.\n\nAs an abundance of caution, to avoid malicious backup attacks, you should not verify your new logins using emoji/QR verifications methods until patched. Prefer using verify with passphrase.\n\n\n### References\nBlog post: https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients\n\n### For more information\nIf you have any questions or comments about this advisory, e-mail us at [security@matrix.org](mailto:security@matrix.org).","aliases":[{"alias":"CVE-2022-39248"},{"alias":"GHSA-fpgf-pjjv-2qgm"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/80107?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.5.1","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.5.1"}],"affected_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/261033?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@0.0.2","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-k87r-mnjz-tkc9"},{"vulnerability":"VCID-mwm6-1d7e-mfev"},{"vulnerability":"VCID-r2zf-yxr7-gke9"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@0.0.2"},{"url":"http://public2.vulnerablecode.io/api/packages/261034?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.2.1","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-mwm6-1d7e-mfev"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.2.1"},{"url":"http://public2.vulnerablecode.io/api/packages/39388?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.2.2","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.2.2"},{"url":"http://public2.vulnerablecode.io/api/packages/334446?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.0","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.0"},{"url":"http://public2.vulnerablecode.io/api/packages/334447?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.2","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.2"},{"url":"http://public2.vulnerablecode.io/api/packages/334448?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.4","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.4"},{"url":"http://public2.vulnerablecode.io/api/packages/334449?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.7","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.7"},{"url":"http://public2.vulnerablecode.io/api/packages/334450?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.8","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.8"},{"url":"http://public2.vulnerablecode.io/api/packages/334451?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.9","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.9"},{"url":"http://public2.vulnerablecode.io/api/packages/334452?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.10","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.10"},{"url":"http://public2.vulnerablecode.io/api/packages/334453?format=json","purl":"pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.13","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-dvrk-p9dt-y7h6"},{"vulnerability":"VCID-vx5q-mbn5-8kcf"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:maven/org.matrix.android/matrix-android-sdk2@1.3.13"},{"url":"http://public2.vulnerablecode.io/api/packages/334454?format=json","purl":"pkg:maven/org.matrix.android/matrix-and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