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custodian-enqueue
-----------------
We open named files from the user to parse tests. The configuration file(s)
are currently opened by root, via /etc/service/custodian-enqueue. This should
be changed to run as a lower-privileged user.
custodian-dequeue
-----------------
Two tests pass arguments from the configuration file to the shell:
ping
http/https
The hostname used to ping, and the URL for web-tests, are both passed directly to the shell assuming they match the following regular expression:
^([^\s]+)\s+
So the following configuration file potentially allows a command to be executed by our worker:
$(/home/steve/hg/custodian/exploit.sh) must ping otherwise "Owned".
http://$(/tmp/exploit.sh)/ must run http with status 200 otherwise "Owned".
Given that anybody who can talk to the beanstalkd server can submit JSON-encoded-jobs we cannot rely on catching this solely in the parser.
For the moment we've solved the case of the ping-exploitation, by validating
that hostnames passed to the multi-ping command match ^[a-z0-9.-]$ - both forms
of input are validated:
* Ensuring the hostname is valid prior to executing the shell command.
* Ensure the hostname is valid before adding the job to the queue.
For HTTP-testing we're avoiding the shell by using the array-based invokation
of the curl command. We don't perform validation on the URL though, because
that is a significantly harder jhob.
General
-------
We decode arbitrary JSON from the queue. We should sign it, or validate it to will prevent trojan malformed
JSON from being added.
At the moment we ensure that the job-body we retrieve looks JSON-like, and decodes to a non-empty hash.
Problem: We cannot sign the body without giving away our key details.
Solution: Read /etc/custodian/salt, and store the checksum of all keys + values with that salt?
TODO
----
Anything else? DoS attacks?
Steve
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