If you are new to Burp and are having problems, please first read the
help on Getting Started with Burp Suite,
and follow the instructions there. Otherwise, the problems and solutions
below might help you.
- Burp doesn't run.
Make sure you have a
suitable version of Java
installed. Then start
Burp from the command line. Look at any error messages or other
output that appears on the command line, which should indicate the cause
of the problem.
- I get an error message saying NoClassDefFoundError.
running Burp from the command line, make sure you have included the
argument followed by the location of the Burp JAR file. If you're still
having problems, check that your command is launching the correct
version of Java. Run the command java -version
and confirm that the version being executed is 1.6 or later. If you have
installed a later version of Java but an older version is still being
executed, then replace "java" with an absolute path to the correct java
executable on your system. If you're still having problems, your Java
installation might be corrupted, so reinstall it.
If you get this error message when trying to launch Burp with a Burp
Extender plugin, then check that your BurpExtender class is declared in the
burp package, and resides inside a folder called burp within your
extension's JAR file.
- I've unpacked the Burp JAR file. What next?
You don't need to unpack or unzip the Burp JAR file. This probably
happened because your computer is associating the .JAR file extension
with some unarchiving software. You can change this association to
associate with Java, or better, you can
Burp from the command line.
- My browser can't make any requests.
browser is always waiting and not showing any actual content, then
please try the following steps. After each step, check whether you are
still having problems, and only continue to the next step if things are
- In Burp, go to the Proxy tab, and the Intercept sub-tab. If this
is showing an intercepted HTTP request, then turn off interception
(click on the "Intercept is on" button to toggle the interception
status). Your browser should now work as normal. See
Getting Started with Burp Proxy
for more help on the basics of using Burp Proxy.
- Try visiting another domain with your browser (ideally a
well-known public domain). If this works,
then the problem might relate to the specific web site you
- Go to the Proxy tab, and the Options sub-tab. In the Proxy
Listeners section, the table should show at least one entry where
the Running checkbox is checked. If this is unchecked, try to check
it. If the box cannot be checked, and the Alerts tab shows a message
saying "Failed to start proxy service" then Burp is not able to open
the specified port and interface. This is often because the port is
in use by another process. Select the item in the table, click the
"Edit" button, and change the port number to a different one. Click
"OK" and see whether the listener can now be enabled. You may need
to try a few different ports, or query your computer's configuration
to locate an available port. Then proceed to the next step to update
your browser's proxy configuration with the new port number.
- Check that your browser's proxy settings are correctly
configured, and are using the same IP address and port number as
configured in a running Proxy listener (in Burp's default settings,
this is IP address 127.0.0.1 and port 8080, may be different in your current configuration). For further details,
see Configuring Your
- In Burp, go to the Options tab, and the Connections sub-tab. In
the "Upstream Proxy Servers" section, confirm whether any upstream
proxies are configured, and if so whether these settings are correct
for your network's setup.
- Make some more requests from your browser (e.g. press refresh a
few times). Look in the Alerts tab to see if any new entries are
being generated. If so, these entries might indicate the cause of
- Go to the Burp menu, and select "Restore defaults" for all
options. Then close Burp down gracefully by selecting "Exit" from
the Burp menu. Start Burp again. Shut down all your browser
instances, and then open a new browser window.
- Burp isn't intercepting anything.
In Burp, go to the Proxy tab, and the History sub-tab. Make some more
requests from your browser (e.g. press refresh a few times), and check
whether any new entries are appearing in the Proxy history. If so, then
Burp is processing your browser traffic but is not presenting any
messages for interception. Go to the Proxy Intercept tab, and enable
master interception (click on the "Intercept is off" button to toggle
the interception status). Then go to the Proxy Options tab, and click
the "Restore defaults" button in the "Intercept Client Requests" and
"Intercept Server Responses" sections. Make some more requests from your
browser, and these should now appear in the Proxy Intercept tab.
If your browser is loading pages correctly but no items are appearing in
the Proxy history, you need to check your browser proxy settings. Your
browser should be configured to use Burp for both HTTP and HTTPS; any
"automatic" proxy options should be disabled, and any "exceptions" to
the proxy settings should be removed. If you are unsure, follow
carefully the steps in
Configuring Your Browser to ensure your browser is correctly set up.
- Burp isn't intercepting HTTPS requests.
If your browser is sending HTTP requests through Burp, but not HTTPS
requests, then your browser is probably configured to proxy only HTTP.
Check in your browser proxy settings that the browser is configured to
use Burp for both protocols. If you are unsure, follow carefully the
steps in Configuring Your
Browser to ensure your browser is correctly set up.
- HTTPS websites don't work properly.
browser is able to load HTTPS websites via Burp, but these do not
function properly (e.g. the user interface is not complete or fully
functional), then the application is probably attempting to load script
code or other resources over HTTPS from another domain, and your browser
is generating a security alert when loading these resources via Burp.
You need to install Burp's
CA certificate in your browser, to ensure that applications using
HTTPS function properly.
- I get authentication failures when using Burp.
the application you are testing uses platform authentication (which
normally shows as a popup login dialog within your browser), and you get
authentication failure messages when your browser is configured to use
Burp, then you need to configure Burp to handle the platform
authentication instead of your browser. Go to the Options tab, and the
Connections sub-tab, and the Platform Authentication section. Add a new
entry for each hostname used by your application, configuring the
authentication type and your credentials. If you aren't sure of the
authentication type, then first try NTLMv2, then NTLMv1, and then the other
types. You may need to close all browser windows and open a new browser
window, to prevent any browser caching from interfering with the
- Burp runs out of memory.
Burp is constrained by the amount of memory that your computer makes
available to the Java process. You can request additional memory for
Burp by starting Burp from the command line using the -Xmx argument. See
Launching Burp for
- How do I run a scan?
Burp is designed to be used
in a user-driven manner, to support the process of testing an
application using hands-on techniques. Conventional web scanners, which
attempt to fully automate the scanning process, have inherent
limitations which mean they provide incomplete coverage. If you want to
use Burp as a conventional scanner, and fully automate the scanning
process, see Using Burp as a Point-and-Click Scanner.
Monday, June 22, 2015
This release updates the Scanner to find super-blind OS command injection vulnerabilities. The Scanner now makes use of Burp Collaborator to find OS command injection vulnerabilities where it is not possible to observe any time delay or command output in responses.
See all release notes ›