Talos Vulnerability Report

SUMMARY

An os command injection vulnerability exists in the httpd delfile.cgi functionality of Siretta QUARTZ-GOLD G5.0.1.5-210720-141020. A specially-crafted HTTP request can lead to arbitrary command execution. An attacker can send an HTTP request to trigger this vulnerability.

CONFIRMED VULNERABLE VERSIONS

The versions below were either tested or verified to be vulnerable by Talos or confirmed to be vulnerable by the vendor.

Siretta QUARTZ-GOLD G5.0.1.5-210720-141020

PRODUCT URLS

QUARTZ-GOLD - https://www.siretta.com/products/industrial-routers/4g-lte-router/gigabit-ethernet-small-footprint-lte-router-eu/

CVSSv3 SCORE

7.2 - CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)

DETAILS

The Siretta QUARTZ-GOLD is an industrial cellular router with several features and services, such as: SSH, UPNP, VPN, SNMP and many others.

The QUARTZ-GOLD router has a web server with several functionalities, a subset of which are related to the management of external files. Indeed, the web-server offers API for uploading files, downloading them, and also deleting if no longer required.

Following the API to delete a previously uploaded file:

void delfile.cgi(void)

{
  [...]

  [... calculate the value of the base_folder variable ...]
  _filename_param = (char *)webcgi_safeget("_filename");                                                        [1]
  filename_ = "";
  if (_filename_param != (char *)0x0) {
    filename_ = _filename_param;
  }
  if (*filename_ != '\0') {
    sprintf(command_buff,"rm -rf %s/%s",base_folder,filename_);                                                 [2]
    system(command_buff);                                                                                       [3]
  }
  [...]
}

The delfile.cgi expects one parameter called _filename that represents the filename of the desired file to be deleted. At [1] the uploaded parameter is taken and then used at [2] for composing the command rm -rf <base_folder>/<_filename>. The composed string is then used at [3] as argument of the system function. The _filename is not sanitized and will be used in the system function, which can lead to an OS command injection.

Exploit Proof of Concept

Sending a request like the following:

POST /delfile.cgi HTTP/1.1
Authorization: Basic <a valid basic auth value>
Content-Length: 48

_filename=`reboot`f&_http_id=<the correct tid>

will cause the device to reboot.

TIMELINE

2022-10-14 - Initial Vendor Contact

2022-10-20 - Vendor Disclosure

2022-11-24 - Vendor Patch Release

2023-01-26 - Public Release