[Snort-users] HELP: "Segmentation Fault" as result of wwwboard passwd.txt attack

Todd Wease twease at ...1935...
Sun Nov 11 09:53:00 EST 2007


Hi Rachmat.  There is an issue in Snort 2.7.0 with GRE and Stream5.  In 
Snort 2.7.0, GRE is considered experimental - it will be fully supported 
in Snort 2.8.1.  The issue is fixed in Snort 2.8.0 so you could try that 
until 2.8.1 comes out.  Just to make sure can you try a couple of things:

(1) reconfigure snort without '--enable-gre' or
(2) use stream4 instead of stream5 or
(3) around line 2807 in src/preprocessors/Stream5/snort_stream5_tcp.c:
...
        /* Flush the server */
        if (tcpssn->server.seglist)
        {
#ifdef GRE
            /* Hack so rebuilt/reinserted packet isn't counted toward 
GRE total
             * Right now, this only works if the delivery protocol is IP
             */
            if (((IPHdr *)(tcpssn->client.seglist->pktOrig + 
ETHERNET_HEADER_LEN))->ip_proto == IPPROTO_GRE)
            {
                pc.gre--;
            }
#endif
...

Change:

if (((IPHdr *)(tcpssn->client.seglist->pktOrig + 
ETHERNET_HEADER_LEN))->ip_proto == IPPROTO_GRE)

to

if (((IPHdr *)(tcpssn->server.seglist->pktOrig + 
ETHERNET_HEADER_LEN))->ip_proto == IPPROTO_GRE)

and rebuild snort.


Let us know if the segfault goes away.

Thanks,
Todd

Rachmat Hidayat Al-Anshar wrote:
> hi guys,
>
> i decided to use pre-patched snort-snortsam-2.7.0 instead snort-2.8.0 
> with snortsam-patch-2.8.
> i compile it with ./configure --enable-dynamicplugin 
> --enable-perfprofiling --with-mysql=/usr/ \
> bin/ --with-mysql-includes=/usr/include/mysql/ 
> --with-mysql-libraries=/usr/lib --enable-gre \
> --enable-timestat
>
> when i try to do wwwboard passwd.txt attack to the snort sensor, i get 
> my snort sensor stop
> processing and show me "segmentation fault" issue. What was going on?
>
> note:
> i set my snort sensor also as web and database server.
>
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