CVE Vulnerabilities

CVE-2016-7124

Deserialization of Untrusted Data

Published: Sep 12, 2016 | Modified: Jan 05, 2018
CVSS 3.x
9.8
CRITICAL
Source:
NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.5 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
4 MODERATE
AV:N/AC:H/Au:N/C:P/I:P/A:N
RedHat/V3
4.8 MODERATE
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Ubuntu
LOW

ext/standard/var_unserializer.c in PHP before 5.6.25 and 7.x before 7.0.10 mishandles certain invalid objects, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via crafted serialized data that leads to a (1) __destruct call or (2) magic method call.

Weakness

The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.

Affected Software

Name Vendor Start Version End Version
Php Php 7.0.0 (including) 7.0.0 (including)
Php Php 7.0.1 (including) 7.0.1 (including)
Php Php 7.0.2 (including) 7.0.2 (including)
Php Php 7.0.3 (including) 7.0.3 (including)
Php Php 7.0.4 (including) 7.0.4 (including)
Php Php 7.0.5 (including) 7.0.5 (including)
Php Php 7.0.6 (including) 7.0.6 (including)
Php Php 7.0.7 (including) 7.0.7 (including)
Php Php 7.0.8 (including) 7.0.8 (including)
Php Php 7.0.9 (including) 7.0.9 (including)
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat rh-php56-0:2.3-1.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat rh-php56-php-0:5.6.25-1.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6 RedHat rh-php56-php-pear-1:1.9.5-4.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS RedHat rh-php56-0:2.3-1.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS RedHat rh-php56-php-0:5.6.25-1.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS RedHat rh-php56-php-pear-1:1.9.5-4.el6 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-php56-0:2.3-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-php56-php-0:5.6.25-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-php56-php-pear-1:1.9.5-4.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS RedHat rh-php56-0:2.3-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS RedHat rh-php56-php-0:5.6.25-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS RedHat rh-php56-php-pear-1:1.9.5-4.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS RedHat rh-php56-0:2.3-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS RedHat rh-php56-php-0:5.6.25-1.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS RedHat rh-php56-php-pear-1:1.9.5-4.el7 *
Php5 Ubuntu precise *
Php5 Ubuntu trusty *
Php5 Ubuntu upstream *
Php7.0 Ubuntu devel *
Php7.0 Ubuntu upstream *
Php7.0 Ubuntu xenial *

Extended Description

It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.

Potential Mitigations

  • Make fields transient to protect them from deserialization.
  • An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

References