Lock Your Doors

Annika Backstrom
in misc, on 26 June 2003. It is tagged #Internet and #Spam.

I'm overdue for a post, so I figured this was as interesting a thing as any. I checked out my Apache logs a few minutes ago, and noticed this interesting line: - - [26/Jun/2003:21:13:50 -0400] ¬
     "CONNECT HTTP/1.0" 302 272 "-" "-"

Being the geek that I am, my curiosity was piqued. It appears that CONNECT is used for tunneling proxy servers. Apparently, these proxies can be used for spam.

I did a port scan, and lo and behold, both SubSeven and Back Orifice were running. Here's the output from a no-frills portscan:

Starting nmap V. 3.00 ( www.insecure.org/nmap/ )
Interesting ports on mars.ritlogic.com (
(The 1583 ports scanned but not shown below are in state: closed)
Port       State       Service
21/tcp     open        ftp
25/tcp     open        smtp
80/tcp     open        http
135/tcp    open        loc-srv
139/tcp    filtered    netbios-ssn
443/tcp    open        https
445/tcp    open        microsoft-ds
1025/tcp   open        NFS-or-IIS
1026/tcp   open        LSA-or-nterm
1433/tcp   open        ms-sql-s
1434/tcp   filtered    ms-sql-m
3372/tcp   open        msdtc
5800/tcp   open        vnc-http
5900/tcp   open        vnc
12345/tcp  filtered    NetBus
12346/tcp  filtered    NetBus
27374/tcp  filtered    subseven
31337/tcp  filtered    Elite

Nmap run completed -- 1 IP address (1 host up) scanned in 10 seconds

Futher investigation in my logs showed 68 CONNECT attempts from 23 different hosts. Here's portscans for 14 of them. As expected, most are running Back Orifice and SubSeven. One is even running pcAnywhere, and VNC shows up more than once.

I might play around with Apache's settings and extensions and see if I can capture the CONNECT data. Might be interesting to see exactly what is coming throught the pipeline. In any case, let this be a lesson to my fellow webmasters: batton down the hatches, the 'net isn't a friendly place.

(Oh, and don't be surprised if my blog page looks like hell in the near future. It needs a style update to fit with the main site, but mostly I need to see a lot less green.)

Update: Looking at my post, I realized that some of these ports (including Back Orifice and SubSeven) are actually filtered, not open. So, really, they might not be running those applications at all. But it still doesn't change the fact that some of these hosts tried to access through my box, so, eh.