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Nmap Development: [patch] support for ip options # [patch] support for ip options This message: [ Message body ] [ More options ] Related messages: [ Next message ] [ Previous message ] Hi guys. Ip options support for nmap can be found here: http://ai.pjwstk.edu.pl/~majek/private/nmap/g14-ipopts-3640.diff (patch is for nmap-4.20ALPHA4) This patch adds new interesting option to nmap. BASIC USAGE for "--ip-options" For the simplest usage we created some templates. They will build ip options for you and you don't need to know the internals. Supported ip options: "R" -> record route (9 slots availble) "T" -> record internet timestamps (9 slots) "U" -> record timestamps and ip addresses (4 slots) "L <hop_ip> ..." -> loose source routing (8 slots) "S <hop_ip> ..." -> strict source routing (8 slots) ADVANCED USAGE There is also possibility of building custom ip options. Consider reading rfc 791. Supported values in parameter: "\xFF" -> hex value "\255" -> decimal value "\x00*16" -> copying char many times BASIC EXAMPLES: RECORD ROUTE: ./nmap -n -sP --packet-trace --ip-options "R" scanme.insecure.org RCVD (0.2790s) ICMP 205.217.153.62 > <censored> Echo reply (type=0/code=0) ttl=46 id=26078 iplen=68 ipopts={ RR{ <3 hops censored> 212.191.126.4 213.248.77.247 213.248.64.225 213.248.64.254 213.248.70.225 64.125.23.14#} EOL} These results are very different from ip's recorded by traceroute. (because are recorded on different interfaces?) <3 hops censored> 4 212.191.224.73 4.770 ms 5.421 ms 5.199 ms 5 213.248.77.213 16.477 ms 17.059 ms 16.887 ms 6 80.91.249.197 16.494 ms 17.055 ms 16.547 ms 7 213.248.65.153 23.255 ms 22.696 ms 23.263 ms 8 80.91.249.216 23.249 ms 22.768 ms 22.854 ms 9 129.250.9.221 23.395 ms 23.229 ms 23.096 ms INTERNET TIMESTAMP (flags = 0) ./nmap -n -sP --packet-trace --ip-options "T" 7thguard.pl RCVD (0.1170s) ICMP 217.73.31.27 > <censored> Echo reply (type=0/code=0) ttl=58 id=16559 iplen=68 ipopts={ TM{[5 hosts not recorded] 2293415244 2390625 1806394 1806403 1806411 1806412 1806412 1806412 1806412#}} Okay, maybe these timestamps (milliseconds from midnight) aren't very interesting. But number of not recorded hosts is quite interesting. We can count number of hops to target using this formula nhops = (<guess_this>*15 + <hosts_not_recorded> + <hosts_recorded(usually=9)>)/2 In these case we will have (0*15+5+9)/2=7 hops. INTERNET TIMESTAMP (flags = 1 <record timestamp and ip>) ./nmap -n -sP --packet-trace --ip-options "U" 7thguard.pl RCVD (0.0710s) ICMP 217.73.31.27 > <censored> Echo reply (type=0/code=0) ttl=58 id=16560 iplen=64 ipopts={ TM{[9 hosts not recorded] <cens>.1.2_at_2293429127 <cens>.1.1_at_2529464 <cens>.255.218_at_1945236 193.87.3.226_at_1945235#}} Now we have timestamps with ip's. Nothing important. LOOSE SOURCE ROUTE: We can select middle hops. ./nmap -n -sS -p139 --packet-trace --ip-options "S 192.168.1.1 10.0.0.3" 10.0.0.5 RCVD (0.0100s) ICMP 10.0.0.5 > 192.168.1.4 Echo reply (type=0/code=0) ttl=126 id=38262 iplen=44 ipopts={ NOP LSRR{ 10.0.0.3 192.168.1.1 192.168.1.1#}} STRICT SOURCE ROUTE: Again, we can select middle hops. RCVD (0.0120s) ICMP 10.0.0.5 > 192.168.1.4 Echo reply (type=0/code=0) ttl=126 id=38255 iplen=44 ipopts={ NOP SSRR{ 10.0.0.3 192.168.1.1 192.168.1.1#}} EXAMPLE BASIC OS DETECTION (windows/linux): Let's send some bogus ip option: ./nmap -n -sO -p1 -PE --max-retries 0 --packet-trace --ip-options "\1\8\3\4" <target> SENT (0.0070s) ICMP 192.168.1.4 > 10.0.0.3 Echo request (type=8/code=0) ttl=48 id=11837 iplen=32 ipopts={ NOP ??{\x08\x03\x04}} Linux responce: RCVD (0.0080s) ICMP 10.0.0.3 > 192.168.1.4 Echo reply (type=0/code=0) ttl=64 id=29711 iplen=28 Windows responce: RCVD (0.0060s) ICMP 10.0.0.5 > 192.168.1.4 Echo reply (type=0/code=0) ttl=128 id=21351 iplen=32 ipopts={ NOP ??{\x08\x03\x04}} Linux removed bugus/unsupported option, windows left it without changes. Other thing is order of options. Linux is changing sequence, windows is leaving it as it was. Of course this kind of detecting OS is as obscure as looking on ttl field. EXAMPLE OF TEST IF LOOSE ROUTE IS ENABLED: My ip 192.168.1.4, tested host 10.0.0.3. Packet is created with custom loose source route field (type=131). I would get back this packet if loose route is enabled. ./nmap -n -sO -p1 -PE --max-retries 0 --packet-trace --ip-options "\1\131\7\4\192\168\1\4" 10.0.0.3 SENT (0.0070s) ICMP 192.168.1.4 > 10.0.0.3 Echo request (type=8/code=0) ttl=42 id=50362 iplen=36 ipopts={ NOP LSRR{#192.168.1.4}} RCVD (0.0080s) ICMP 192.168.1.4 > 192.168.1.4 Echo request (type=8/code=0) ttl=40 id=50362 iplen=36 ipopts={ NOP LSRR{ 192.168.1.3#}} We sent echo request, target forwarded this request back -> loose routing is working. Let's try different host: SENT (0.0060s) ICMP 192.168.1.4 > 10.0.0.5 Echo request (type=8/code=0) ttl=39 id=28683 iplen=36 ipopts={ NOP LSRR{#192.168.1.4}} RCVD (0.0070s) ICMP 10.0.0.5 > 192.168.1.4 source route failed (type=3/code=5) ttl=128 id=21357 iplen=64 Source routing is not working. And my favorite useless example: ./nmap -n -sO -p1 -PE --max-retries 0 --packet-trace -e eth0 --ip-options "L 192.168.1.3" 127.0.0.1 Linux is just dropping this packet with no response. EXAMPLE OF STRICT ROUTE USAGE FOR NETWORK DISCOVERY: When using strict source route, router must have next ip address directly on link. This allows us to check what networks are connected to such host. Scan target 192.168.1.1 is router nearest to me. Lets try first net: ./nmap -n -sO -p1 -PE --max-retries 0 --packet-trace --ip-options "S 192.168.1.1" 172.0.0.123 SENT (0.0060s) ICMP 192.168.1.4 > 192.168.1.1 Echo request (type=8/code=0) ttl=40 id=57758 iplen=40 ipopts={ NOP SSRR{#192.168.1.1 172.0.0.123}} RCVD (0.0060s) ICMP 192.168.1.1 > 192.168.1.4 source route failed (type=3/code=5) ttl=64 id=29720 iplen=68 Nope, network 172.0.0. not present. The same probe with host 10.0.0.123 results in no answer. Packet went into darnkess, but network is probably present. Of course the main advantage of loose/strict route is that you can scan bypass some misconfigured acl's on routers. Some simillar information can be found in my previous email: http://seclists.org/lists/nmap-dev/2006/Apr-Jun/0431.html You should notice that while OS detection sending ip options is disabled. It's recommended not to use ip options and os detection at the same time. Cheers, Marek Majkowski _______________________________________________ Sent through the nmap-dev mailing list http://cgi.insecure.org/mailman/listinfo/nmap-dev Received on Jul 06 2006 This message: [ Message body ] Next message: stripe dog: "Screen Shots" Previous message: Fyodor: "Re: [PATCH] new --min-retries options" Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]
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