CVE-2021-3374: Directory traversal in RStudio Shiny Server before 1.5.16 allows attackers to read the application source code, involving an encoded slash.

PriorityP346medium5.3CVSS 3.1

AVNACLPRNUINSUCLINAN

EXPLOIT

EPSS

14.25%

96.1th percentile

Directory traversal in RStudio Shiny Server before 1.5.16 allows attackers to read the application source code, involving an encoded slash.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
rstudio	shiny_server	< 1.5.16	1.5.16

Detection & IOCsextracted from sources · hover to see the quote

url{{BaseURL}}/%2f/↗

url{{BaseURL}}/sample-apps/hello/%2f/↗

path/sample-apps/hello/%2f/↗

→HTTP GET request with an encoded slash (%2f) appended to the URL path triggers directory listing; look for 'Index of /' in the response body with HTTP 200 status. ↗
→Response body contains 'Index of /' string indicating directory traversal success. ↗
→Response body contains filenames matching the regex [A-Za-z].*\.R, indicating R source code file leakage. ↗
→Vulnerable endpoint path /sample-apps/hello/ is a known default Shiny Server application path; probe with %2f suffix to confirm exposure. ↗

·Vulnerability only affects Rstudio Shiny Server versions prior to 1.5.16; patched versions are not exploitable via this technique. ↗
·The CPE scope covers the 'pro' edition specifically; verify whether open-source edition is equally affected before applying detections broadly. ↗

CVSS provenance

nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N

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