CVE-2022-22965
Description
A flaw was found in Spring Framework, specifically within two modules called Spring MVC and Spring WebFlux, (transitively affected from Spring Beans), using parameter data binding. This flaw allows an attacker to pass specially-constructed malicious requests to certain parameters and possibly gain access to normally-restricted functionality within the Java Virtual Machine.
Security Bulletin
Statement
The reporter of this flaw provided a proof-of-concept that relied on Apache Tomcat; it accessed the classloader and changed logging properties to place a web shell in Tomcat's root directory, and was able to call various commands subsequently.
There are several conditions required to achieve this exploit: -Java 9 or newer version -Apache Tomcat as the Servlet container -packaged as WAR file -spring-webmvc or spring-webflux dependency -no protections in place against malicious data bindings (ex: WebDataBinder allow list)
There may be other exploit paths than this, possibly not utilizing Tomcat.
Mitigation
For those who are not able to upgrade affected Spring classes to the fixed versions, there is a workaround customers can implement for their applications, via setting disallowed fields on the data binder, and denying various iterations of the string "class.*"
For full implementation details, see Spring's early announcement post in the "suggested workarounds" section: https://spring.io/blog/2022/03/31/spring-framework-rce-early-announcement#suggested-workarounds
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.1 | 9.8 | 9.8 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
There are several conditions which are beyond the attacker's control needed for a successful exploit of this flaw: specific runtime versions, specific servlet container, specific type of packaging, specific dependencies needed, and no protective measures in the application against malicious data bindings. This situation is better reflected by Access Complexity: High rather than Low, and an Impact of Important.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
In some cases, injectable code controls authentication; this may lead to a remote vulnerability.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Injected code can access resources that the attacker is directly prevented from accessing.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
When a product allows a user's input to contain code syntax, it might be possible for an attacker to craft the code in such a way that it will alter the intended control flow of the product. As a result, code injection can often result in the execution of arbitrary code. Code injection attacks can also lead to loss of data integrity in nearly all cases, since the control-plane data injected is always incidental to data recall or writing.
Non-Repudiation
Technical Impact: Hide Activities
Often the actions performed by injected control code are unlogged.
Frequently Asked Questions
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