CVE-2017-11153

published 2017-08-08

CVE-2017-11153: Deserialization vulnerability in synophoto_csPhotoMisc.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to gain…

Priority P2 73 critical 9.8 CVSS 3.0

AV N AC L PR N UI N S U C H I H A H

EXPLOIT

Deserialization vulnerability in synophoto_csPhotoMisc.php in Synology Photo Station before 6.7.3-3432 and 6.3-2967 allows remote attackers to gain administrator privileges via a crafted serialized payload.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
synology	photo_station	<= 6.7.2-3429	—
synology	photo_station	—	—
synology	synology_photo_station	—	—

Detection & IOCs extracted from sources · hover to see the quote

path /photo/include/synotheme_upload.php↗

path /photo/include/file_upload.php↗

path /photo/admin/general_setting.php↗

path /photo/PixlrEditorHandler.php↗

path /photo/facebook/exploit.php↗

path /../../../../../var/packages/PhotoStation/etc/blog/photo_custom_preview_logo.png↗

path /../../../../../var/services/photo/@eaDir/SYNOPHOTO_THEME_DIR/photo_custom_preview_logo.png↗

path /volume1/photo/../../../volume1/@appstore/PhotoStation/photo/facebook/exploit↗

other data://text/plain;base64,<payload>↗

• → Detect POST requests to /photo/include/synotheme_upload.php with action=logo_upload containing a serialized PHP session string as the uploaded file body — this is the first stage of the exploit chain used to plant a fake admin session. ↗
• → Detect POST requests to /photo/include/file_upload.php with a 'session' parameter containing path traversal sequences (e.g., /../../../../../) — this is used to load the planted serialized session file and authenticate as a fake admin. ↗
• → Detect POST requests to /photo/PixlrEditorHandler.php with type=php and a base64-encoded data:// URI in the 'image' parameter — this is the webshell/arbitrary PHP file write stage. ↗
• → Detect GET requests to /photo/facebook/exploit.php — this path is used to trigger execution of the attacker-uploaded PHP webshell. ↗
• → The deserialization vulnerability resides in synophoto_csPhotoMisc.php; monitor for crafted serialized PHP payloads (strings beginning with 'root|a:' or containing 'admin_syno_user') delivered to Photo Station endpoints. ↗
• → The full exploit chain results in code execution as uid=138862(PhotoStation); alert on processes spawned under this UID on Synology NAS devices. ↗

• · The session file drop path varies by Photo Station version; two alternative traversal paths are used depending on the installed version. ↗
• · The exploit is a chained 4-vulnerability attack; blocking any single stage (file upload, fake auth, privilege escalation, or code execution) may break the chain but does not remediate the underlying deserialization flaw. ↗

CVSS provenance

nvd v3.0 9.8 CRITICAL CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v2.0 7.5 HIGH AV:N/AC:L/Au:N/C:P/I:P/A:P

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