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sCap - Version: 1.0 build 31

sCap is open source commandline application project which uses system raw sockets and makes you able to scan, capture and hexdump incoming tcp/udp/icmp traffic without libcap. Software is written for educational purposes and is distributed in the hope that it will be useful for anyone interested in this field.

Usage

scap [-i] [-d] [-h]
options are:
 -i         # dump header info in file
 -d         # dump data in file
 -h         # print help and usage
 -o filename # export output to PCAP file
 -s ip_src   # filter packets by IP source
 -t ip_dst   # filter packets by IP destination
 -p port_src # filter packets by source port
               will filter TCP and UDP only
 -q port_src # filter packets by destination port
               will filter TCP and UDP only
 -l ttl_min  # filter packets by minimun TTL
 -m ttl_max  # filter packets by maximum TTL
 -f frag_min # filter packets by minimum fragment number
 -g frag_max # filter packets by maximun fragment number

With option -i, you can capture incoming traffic and log ip/udp/tcp/icmp headers in file. If you add option -d, sCap will capture headers and also it will hexdump incoming traffic data in log file. Without those arguments, sCap only counts numbers of incoming packets.

Installation

Compilation of this project is possible with Makefile and build script.

git clone https://github.com/kala13x/scap.git
cd scap
chmod +x build.sh
./build.sh

Script will build whole project and move binary file into bin directory of scap project.

How to use

sCap requires root access because of binding raw socket. When you launch sCap it only counts numbers of packets, but at the some time you can tail log file to see dumped data.

Example of log file output

2015.05.09-20:30:38 - [LIVE] Captured IP Header
2015.05.09-20:30:38 - [IP] Version : 4
2015.05.09-20:30:38 - [IP] Header Length : 5 DWORDS or 20 Bytes
2015.05.09-20:30:38 - [IP] Type Of Service : 40
2015.05.09-20:30:38 - [IP] Total Length : 83 Bytes(Size of Packet)
2015.05.09-20:30:38 - [IP] Identification : 4923
2015.05.09-20:30:38 - [IP] TTL : 53
2015.05.09-20:30:38 - [IP] Protocol : 6
2015.05.09-20:30:38 - [IP] Checksum : 46234
2015.05.09-20:30:38 - [IP] Source IP : 192.30.252.87
2015.05.09-20:30:38 - [IP] Destination IP : 192.168.0.137

2015.05.09-20:30:38 - [LIVE] Captured TCP Packet
2015.05.09-20:30:38 - [TCP] Source Port : 443
2015.05.09-20:30:38 - [TCP] Destination Port : 41324
2015.05.09-20:30:38 - [TCP] Sequence Number : 472573572
2015.05.09-20:30:38 - [TCP] Acknowledge Number : 2250858137
2015.05.09-20:30:38 - [TCP] Header Length : 8 DWORDS or 32 BYTES
2015.05.09-20:30:38 - [TCP] Urgent Flag : 0
2015.05.09-20:30:38 - [TCP] Acknowledgement Flag : 1
2015.05.09-20:30:38 - [TCP] Push Flag : 1
2015.05.09-20:30:38 - [TCP] Reset Flag : 0
2015.05.09-20:30:38 - [TCP] Synchronise Flag : 0
2015.05.09-20:30:38 - [TCP] Finish Flag : 0
2015.05.09-20:30:38 - [TCP] Window : 31
2015.05.09-20:30:38 - [TCP] Checksum : 12061
2015.05.09-20:30:38 - [TCP] Urgent Pointer : 0

2015.05.09-20:30:38 - [IP] Header
    45 28 00 53 13 3B 40 00 35 06 B4 9A C0 1E FC 57 E     (.S.;@.5......W
    C0 A8 00 89                                           ....
    
2015.05.09-20:30:38 - [TCP] Header
    01 BB A1 6C 1C 2A E6 84 86 29 5E 99 80 18 00 1F       ...l.*...)^.�...
    2F 1D 00 00 01 01 08 0A 40 9D 7A BE 01 4C CD 9C       /.......@.z..L..

2015.05.09-20:30:38 - [DATA] Payload
    16 03 03 00 5A 02 00 00 56 03 03 55 4F 66 FC DC       ....Z...V..UOf..
    CC 35 04 28 FC C8 1A 72 1E 72 F6 99 5D B1 ED 6E       .5.(...r.r..]..n
    88 60 FD B7 D6 AF 00 9E 42 68 96 20 50 32 17 BA       .`......Bh. P2..
    D9 65 D5 14 53 A7 00 99 42 72 00 A8 E4 16 C3 34       .e..S...Br.....4
    01 D6 D5 24 1A 6C 50 6F D4 EE A3 65 C0 2F 00 00       ...$.lPo...e./..
    0E FF 01 00 01 00 00 10 00 05 00 03 02 68 32 14       .............h2.
    03 03 00 01 01 16 03 03 00 28 00 00 00 00 00 00       .........(......
    00 00 1B F6 B0 46 AD 42 77 BC C7 7D B0 6F 2A DB       .....F.Bw..}.o*.
    2C 8F 94 58 C7 F4 04 6C 37 66 94 0E 0F BC 0D 44       ,..X...l7f.....D
    5B A2                                                 [.

Feel free to fork

You can fork, modify and change the code unther the GNU GPL 3 license. The project contains LICENSE file to see full license description.

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