CloudBees Jenkins和LTS 跨站脚本漏洞 CVE-2020-2229

# CloudBees Jenkins和LTS 跨站脚本漏洞 CVE-2020-2229

CloudBees Jenkins（Hudson Labs）是美国CloudBees公司的一套基于Java开发的持续集成工具。该产品主要用于监控持续的软件版本发布/测试项目和一些定时执行的任务。LTS是CloudBeesJenkins的一个长期支持版本。

CloudBees Jenkins 2.251及之前版本和LTS 2.235.3及之前版本中存在跨站脚本漏洞。该漏洞源于WEB应用缺少对客户端数据的正确验证。攻击者可利用该漏洞执行客户端代码。

Exploit:

“`
# Exploit Title: Jenkins 2.235.3 – ‘tooltip’ Stored Cross-Site Scripting
# Date: 11/12/2020
# Exploit Author: gx1
# Vendor Homepage: https://www.jenkins.io/
# Software Link: https://updates.jenkins-ci.org/download/war/
# Version: <= 2.251 and <= LTS 2.235.3 # Tested on: any # CVE : CVE-2020-2229 # References: https://www.jenkins.io/security/advisory/2020-08-12/#SECURITY-1955 https://www.openwall.com/lists/oss-security/2020/08/12/4 Vendor Description: Jenkins 2.251 and earlier, LTS 2.235.3 and earlier does not escape the tooltip content of help icons. Tooltip values can be contributed by plugins, some of which use user-specified values. This results in a stored cross-site scripting (XSS) vulnerability. Jenkins 2.252, LTS 2.235.4 escapes the tooltip content of help icons. Technical Details and Exploitation: As it is possible to observe from patch commit: https://github.com/jenkinsci/jenkins/pull/4918/commits/c991b45b5bae09f9894acdc1f1fb1d8809fe6ef6 The fix to solve the vulnerability is applied to 'core/src/main/resources/lib/layout/svgIcon.jelly' tooltip attribute:

svgIcon is a layout element belonging to jenkins core: https://reports.jenkins.io/core-taglib/jelly-taglib-ref.html#layout:svgIcon
As suggested by Jenkins documentation (https://www.jenkins.io/doc/developer/security/xss-prevention/)
“Note that this only affects the use of ${…} among PCDATA, and not in attribute values, so that Jelly tag invocations don’t result in surprising behavior.”
Tooltip attribute can contain HTML code, as suggested in form section: https://www.jenkins.io/doc/developer/forms/adding-tool-tips/
For this reason, it is possible to inject XSS code in a Jenkins system by uploading a plugin that contains an element containing a malicious XSS payload in tooltip attribute:

“>

This creates an icon that triggers the Cross-Site Scripting when the mouse is over and opens tooltip. Obviously, you can use css and large size and height to generate a svg element that covers all the screen in order to trigger the XSS when the user navigates the page.

Solution:

The following releases contain fixes for security vulnerabilities:
* Jenkins 2.252
* Jenkins LTS 2.235.4
“`

ref:

https://www.anquanke.com/vul/id/2119266

https://www.exploit-db.com/exploits/49232