Evangelos Deirmentzoglou - GSoC status report #5 of 17

[Evangelos Deirme <edeirme () gmail com>]

Hey everyone,

This is my report for the 5th week of GSoC 2017.

---Status Report #5 of 17---

12 June 2017

Accomplishments:

   - Enriched the ssh-brute.nse script with the setReduce attribute of
   brute.lua. When an ERROR or EOF message is detected, ssh-brute will reduce
   the number of the used threads. Due to the fact that those errors currently
   occur only in the “connect” phase of the script, a small modification was
   made to brute.lua. The reason for those changes was that brute.lua will
   respect the “setReduce” option only if it is set from the “login” phase of
   the NSE script. The changes of brute.lua which may be subject to change can
   be found at the following link:
   https://github.com/edeirme/nmap/commit/e634a91d1608d2e7a0d1e61556cc99312aad0951
   - My research on the EOF/ERROR messages is done. The EOF message is
   present in the receive_callback function located in the nse_nsock.cc file.
   The value EOF or ERROR can be found in the nse.status element of that
   function. This function is used as a callback of the nscok_read() function
   of the same file. Those messages are a result of TCP connection cut loose
   by the server when it feels stressed. In both cases, a TCP handshake is
   achieved and immediately closed (FYN ACK, ACK). Once the TCP connection is
   closed, nmap sends an SSH packet which as it is expected receives an RST
   packet. Both of those messages (EOF, ERROR), when received in the “connect”
   phase of the brute, can safely be ignored.

Priorities:

   - Compile nmap with ssh-brute in Windows
   - Push changes to main branch

Thanks,

Evangelos Deirmentzoglou

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