MESSAGE
| DATE | 2005-06-08 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [NYLXS - HANGOUT] ssh help
|
/*
* SSHLOCKOUT_PF.C
*
* Written by Matthew Dillon
* Modified to use PF tables by Scott Ullrich
*
* Use: pipe syslog auth output to this program. e.g. in /etc/syslog.conf:
*
* auth.info;authpriv.info /var/log/auth.log
* auth.info;authpriv.info |exec /root/adm/sshlockout
*
* Detects failed ssh login and attempts to map out the originating IP
* using PF's tables.
*
* setup a rule in your pf ruleset (near the top) similar to:
* block in log quick from to any label "sshlockout"
*
* *VERY* simplistic. ipfw entries do not timeout, duplicate entries may
* occur (though normally not since ssh won't see new connections from
* the IP otherwise), there are no checks made for local IPs or nets,
* or for prior successful logins, etc.
*/
#include
#include
#include
#include
#include
#include
static void lockout(char *str);
int
main(int ac, char **av)
{
char buf[1024];
char *str;
openlog("sshlockout", LOG_PID|LOG_CONS, LOG_AUTH);
syslog(LOG_ERR, "sshlockout starting up");
freopen("/dev/null", "w", stdout);
freopen("/dev/null", "w", stderr);
while (fgets(buf, sizeof(buf), stdin) != NULL) {
if (strstr(buf, "sshd") == NULL)
continue;
if ((str = strstr(buf, "Failed password for root from")) != NULL ||
(str = strstr(buf, "Failed password for admin from")) != NULL
) {
while (*str && (*str < '0' || *str > '9'))
++str;
lockout(str);
continue;
}
if ((str = strstr(buf, "Failed password for invalid user")) != NULL) {
str += 32;
while (*str == ' ')
++str;
while (*str && *str != ' ')
++str;
if (strncmp(str, " from", 5) == 0)
lockout(str + 5);
continue;
}
if ((str = strstr(buf, "Illegal user")) != NULL) {
str += 12;
while (*str == ' ')
++str;
while (*str && *str != ' ')
++str;
if (strncmp(str, " from", 5) == 0)
lockout(str + 5);
}
}
syslog(LOG_ERR, "sshlockout exiting");
return(0);
}
static void
lockout(char *str)
{
int n1, n2, n3, n4;
char buf[256];
if (sscanf(str, "%d.%d.%d.%d", &n1, &n2, &n3, &n4) == 4) {
syslog(LOG_ERR, "Detected Illegal ssh login attempt, locking out
%d.%d.%d.%d\n", n1, n2, n3, n4);
snprintf(buf, sizeof(buf), "/sbin/pfctl -t sshlockout -T add %d.%d.%d.%d
", n1, n2, n3, n4);
system(buf);
}
}
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