cbcvebase.
CVE-2016-8371
published 2018-04-05

CVE-2016-8371: The web server in Phoenix Contact ILC PLCs can be accessed without authenticating even if the authentication mechanism is enabled.

PriorityP261high7.3CVSS 3.0
AVNACLPRNUINSUCLILAL
EXPLOIT
EPSS
11.20%
95.4th percentile
The web server in Phoenix Contact ILC PLCs can be accessed without authenticating even if the authentication mechanism is enabled.

Affected

2 ranges
VendorProductVersion rangeFixed in
composercomposer>= 0 < 1.0.01.0.0
phoenix_contactphoenix_contact_ilc_plcs

Detection & IOCsextracted from sources · hover to see the quote

urlhttp://<host>/cgi-bin/ILRReadValues.exe
urlhttp://<host>/cgi-bin/writeVal.exe
path/cgi-bin/ILRReadValues.exe
path/cgi-bin/writeVal.exe
filenameILRReadValues.exe
filenamewriteVal.exe
  • Detect unauthenticated HTTP GET requests to /<ProjectName>.tcr on Phoenix Contact ILC PLC web servers — this path leaks the full list of PLC tags without any authentication.
  • Detect unauthenticated HTTP POST requests to /cgi-bin/ILRReadValues.exe — this endpoint returns current PLC variable values without requiring authentication.
  • Detect unauthenticated HTTP GET requests to /cgi-bin/writeVal.exe with query parameters — this endpoint allows writing arbitrary values to PLC tags without authentication.
  • Inspect HTTP responses from ILC PLC web root (/) for the string 'ProjectName' in HTML — attackers use this to enumerate the project name before further exploitation.
  • The web server allows access to read and write PLC variables without authentication — alert on any access to ILRReadValues.exe or writeVal.exe from untrusted source IPs.
  • ·The authentication bypass (CVE-2016-8371) affects ALL ILC 1xx PLC versions — there is no version-specific scope; any ILC 1xx device with its web server exposed is vulnerable regardless of whether authentication is configured.
  • ·The exploit also covers CVE-2016-8380 (unauthenticated read/write of PLC variables) and CVE-2016-8366 (cleartext password storage/transfer) — detections targeting these CGI endpoints may surface all three CVEs simultaneously.
  • ·The WebVisit password macro can be configured to store and transfer passwords in cleartext, meaning network captures may expose credentials even on 'protected' HMI pages.

CVSS provenance

nvdv3.07.3HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
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