Network Security Tools

Implementing SMTP-AUTH in Hydra

Every protocol Hydra supports needs to define the following variables and include files:

#include "hydra-mod.h"

extern char *HYDRA_EXIT;

char *buf;

The hydra-mod.h include file defines the functions the module accesses while running. The HYDRA_EXIT string is a value returned by some Hydra functions. The buf pointer is used in hydra-smtpauth.c as a temporary buffer for data received.

void
service_smtpauth(unsigned long int ip, int sp, unsigned char options,
        char *miscptr, FILE * fp, int port)
{
  int run = 1, next_run, sock = -1;
  int myport = PORT_SMTPAUTH, mysslport = PORT_SMTPAUTH_SSL;
  char *buffer = "EHLO hydra\r\n";

The run and next_run variables are used to control the state of the testing session. service_smtpauth follows a convention similar to many of the other text-based protocols supported in Hydra, whereby it is possible to connect and try multiple sets of credentials. The run values are specified in Table 3-3.

Table 3-3. run values

run values	Description
1	Connect or reconnect to the service port.
2	Run the password-testing function on the established connection. You can run this multiple times for one connection for this protocol.
3	Close the connection and exit gracefully.

The sock variable is used to track the status of the connection to the service. The PORT_SMTPAUTH and PORT_SMTPAUTH_SSL values have been added to the hydra.h file, and they are the ports SMTP runs on normally and when run over SSL (ports 25 and 465, respectively). ...