[FD] Blindspot Advisory: Java/Python FTP Injections Allow for Firewall Bypass

["Timothy D. Morgan" <tim.advisories@xxxxxxxxxxxxxxxxxxxxx>]

Overview
Recently, an vulnerability in Java's FTP URL handling code has been published 
which allows for protocol stream injection. It has been shown[1] that this flaw 
could be used to leverage existing XXE or SSRF vulnerabilities to send 
unauthorized email from Java applications via the SMTP protocol. While 
technically interesting, the full impact of this protocol stream injection has 
not been fully accounted for in existing public analysis.

Protocol injection flaws like this have been an area of research of mine for 
the past few couple of years and as it turns out, this FTP protocol injection 
allows one to fool a victim's firewall into allowing TCP connections from the 
Internet to the vulnerable host's system on any "high" port (1024-65535). A 
nearly identical vulnerability exists in Python's urllib2 and urllib libraries. 
In the case of Java, this attack can be carried out against desktop users even 
if those desktop users do not have the Java browser plugin enabled.

As of 2017-02-20, the vulnerabilities discussed here have not been patched by 
the associated vendors, despite advance warning and ample time to do so.
...

For the rest of the advisory, please see:
  
http://blog.blindspotsecurity.com/2017/02/advisory-javapython-ftp-injections.html




1. https://shiftordie.de/blog/2017/02/18/smtp-over-xxe/

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