cbcvebase.
CVE-2018-7171
published 2018-03-30

CVE-2018-7171: Directory traversal vulnerability in Twonky Server 7.0.11 through 8.5 allows remote attackers to share the contents of arbitrary directories via a .. (dot dot)…

PriorityP266high7.5CVSS 3.0
AVNACLPRNUINSUCHINAN
EXPLOIT
EPSS
28.73%
97.9th percentile
Directory traversal vulnerability in Twonky Server 7.0.11 through 8.5 allows remote attackers to share the contents of arbitrary directories via a .. (dot dot) in the contentbase parameter to rpc/set_all.

Affected

2 ranges
VendorProductVersion rangeFixed in
lynxtechnologytwonky_server7.0.11 – 8.5
westerndigitalmy_cloud_firmware

Detection & IOCsextracted from sources · hover to see the quote

urlhttp://<host>:<port>/rpc/set_all
urlhttp://<host>:<port>/rpc/dir?path=/
commandcontentbase=/../
commandcontentdir=/../
port9000
path/rpc/set_all
path/rpc/dir
path/rpc/get_friendlyname
path/rpc/info_status
  • Detect POST requests to /rpc/set_all containing 'contentbase=/../' or 'contentdir=/../' in the body, indicating directory traversal exploitation attempt.
  • Alert on HTTP responses from Twonky Server containing the 'Server: Linux/2.x.x, UPnP/1.0, pvConnect UPnP SDK/1.0, Twonky UPnP SDK/1.1' header, identifying vulnerable server instances.
  • Detect access to /api/2.1/rest/ endpoints using PHPSESSID cookies harvested from /tmp/sess_* files on WDMyCloud devices, indicating post-exploitation REST API abuse.
  • Flag unauthenticated POST requests to /rpc/set_all from external/untrusted IPs; approximately 98% of ~20800 publicly exposed Twonky servers lack password protection.
  • ·The traversal payload uses 'contentbase' in the PoC script but 'contentdir' in the narrative description; both parameter names should be monitored.
  • ·The /rpc/dir endpoint uses different URL formats depending on version: query-string (?path=) for version 8.x and path-style (/path=) for earlier versions.
  • ·The exploit also attempts HTTPS fallback if HTTP connection fails; detection rules should cover both http and https on port 9000.

CVSS provenance

nvdv3.07.5HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
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