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Kojoney (SSH honeypot) remote DoS
From: Nicob <nicob () nicob net>
Date: Tue, 23 Feb 2010 23:59:06 +0100


[=] Affected software : 

        Name : Kojoney
        Description : Low interaction SSH honeypot
        Version : < 0.0.4.2
        Service : TCP/22

[=] Patched version : 

http://sourceforge.net/projects/kojoney/files/kojoney-0.0.4.2.tar.gz/download

[=] Technical details : 

Emulation of the wget and curl commands is made via calls to
urllib.urlopen(url). The only sanity check is the following :

        if url.find("://") == -1:
                url = "http://"; + url

This will catch some attempts to access local files like
"file:/etc/hosts" but requesting "file://localhost/foo/bar" is still
possible.

Under Linux, this can be used to access "file://localhost/dev/urandom".
The kojoney.py process will then use 100% of CPU and will grow in
memory, until killed by the kernel OOM Killer.

[=] Note :

When exploiting urlopen() related vulnerabilities in Python
applications, some little known features can come handy :

data://,HelloWorld
=> returned value is "HelloWorld"

data:text;base64,WDVPIVAlQEFQWzRcUFpYNTQoUF4pN0NDKTd9JEVJQ0FSLVNUQU5EQVJELUFOVElWSVJVUy1URVNULUZJTEUhJEgrSCo=://a
=> returned value is the EICAR test string

And yes, these strings too bypass the "://" Kojoney check ;-)

Nicob 

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