Bug 1297726

Summary:	php: Session WDDX Packet Deserialization Type Confusion Vulnerability
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abhgupta, carnil, cbuissar, dmcphers, fedora, jialiu, jokerman, jorton, kseifried, lmeyer, mmaslano, mmccomas, rcollet, tiwillia, webstack-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	php 5.5.31, php 5.6.17	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-02-03 12:57:48 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1297727
Bug Blocks:	1297732

Description Adam Mariš 2016-01-12 10:27:22 UTC

It was found that attacker can deserialize a string-type ZVAL via php_wddx_deserialize_ex(), which means he is able to create fake HashTable via the Z_ARRVAL_P macro with the string-type ZVAL. This could result in arbitrary remote code execution.

Vulnerable code:

_SERIALIZER_DECODE_FUNC(wddx)
{
	...
	
	MAKE_STD_ZVAL(retval);

	if ((ret = php_wddx_deserialize_ex((char *)val, vallen, retval)) == SUCCESS) {

		for (zend_hash_internal_pointer_reset(Z_ARRVAL_P(retval));
			 zend_hash_get_current_data(Z_ARRVAL_P(retval), (void **) &ent) == SUCCESS;
			 zend_hash_move_forward(Z_ARRVAL_P(retval))) {
			 hash_type = zend_hash_get_current_key_ex(Z_ARRVAL_P(retval), &key, &key_length, &idx, 0, NULL);

Upstream patch:

https://git.php.net/?p=php-src.git;a=commit;h=1785d2b805f64eaaacf98c14c9e13107bf085ab1

Upstream bug (contains reproducer):

https://bugs.php.net/bug.php?id=70741

Comment 1 Adam Mariš 2016-01-12 10:27:57 UTC

Created php tracking bugs for this issue:

Affects: fedora-all [bug 1297727]

Comment 2 Fedora Update System 2016-01-16 13:22:13 UTC

php-5.6.17-1.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.

Comment 3 Fedora Update System 2016-01-16 14:20:30 UTC

php-5.6.17-1.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.

Comment 4 Cedric Buissart 2016-01-29 11:53:05 UTC

Lowering the impact down to moderate based on the following :
 * WDDX packet deserialization should not be used with untrusted source :
http://php.net/manual/en/function.wddx-deserialize.php#refsect1-function.wddx-deserialize-returnvalues