IPy Blacklist Bypass

2014-10-16T00:00:00
ID PACKETSTORM:128722
Type packetstorm
Reporter Nicolas Gregoire
Modified 2014-10-16T00:00:00

Description

                                        
                                            `  
IPy is a Python "class and tools for handling of IPv4 and IPv6 addresses  
and networks" (https://github.com/haypo/python-ipy). This library is  
sometimes used to implement blacklists forbidding internal, private or  
loopback addresses.  
  
Using octal encoding (supported by urllib2), it is possible to bypass  
checks based on the result of the iptype() function. For example, IP  
address '0177.0000.0000.0001' is considered as 'PUBLIC' but resolves to  
'127.0.0.1' when accessed via urllib2.  
  
Developers were informed, no news since then... More details on my blog:  
http://www.agarri.fr/kom/archives/2014/10/15/bypassing_blacklists_based_on_ipy/index.html  
  
Cheers,  
Nicolas Grégoire  
  
  
`