CVE-2017-4995 Information

Description

An issue was discovered in Pivotal Spring Security 4.2.0.RELEASE through 4.2.2.RELEASE and Spring Security 5.0.0.M1. When configured to enable default typing Jackson contained a deserialization vulnerability that could lead to arbitrary code execution. Jackson fixed this vulnerability by blacklisting known \deserialization gadgets.\ Spring Security configures Jackson with global default typing enabled which means that (through the previous exploit) arbitrary code could be executed if all of the following is true: (1) Spring Security’s Jackson support is being leveraged by invoking SecurityJackson2Modules.getModules(ClassLoader) or SecurityJackson2Modules.enableDefaultTyping(ObjectMapper); (2) Jackson is used to deserialize data that is not trusted (Spring Security does not perform deserialization using Jackson so this is an explicit choice of the user); and (3) there is an unknown (Jackson is not blacklisting it already) \deserialization gadget\ that allows code execution present on the classpath. Jackson provides a blacklisting approach to protecting against this type of attack but Spring Security should be proactive against blocking unknown \deserialization gadgets\ when Spring Security enables default typing.

CVSS Vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Reference

http://www.securityfocus.com/bid/99080 https://lists.apache.org/thread.html/4641ed8616ccc2c1fbddac2c3dc9900c96387bc226eaf0232d61909b@3Ccommits.cassandra.apache.org3E https://pivotal.io/security/cve-2017-4995

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.1