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https://github.com/al0ne/Nmap_Bypass_IDS
Nmap&Zmap特征识别，绕过IDS探测
https://github.com/al0ne/Nmap_Bypass_IDS
bypass nmap suricata zmap
Last synced: 21 days ago
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Nmap&Zmap特征识别，绕过IDS探测
- Host: GitHub
- URL: https://github.com/al0ne/Nmap_Bypass_IDS
- Owner: al0ne
- Created: 2018-12-21T04:40:18.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2019-08-01T02:53:31.000Z (over 5 years ago)
- Last Synced: 2024-08-05T17:30:53.948Z (4 months ago)
- Topics: bypass, nmap, suricata, zmap
- Homepage:
- Size: 4.88 KB
- Stars: 326
- Watchers: 6
- Forks: 60
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-hacking-lists - al0ne/Nmap_Bypass_IDS - Nmap&Zmap特征识别，绕过IDS探测 (Others)
README
# Nmap_Bypass_IDS
扫描参数：nmap -sS -sV -O -vv 1.1.1.1
### nmap 系统识别绕过ids检测
nmap使用-O参数扫描时会发送tcp，udp，icmp 然后在根据响应的tcp window，TTL，IPID等对比指纹库识别操作系统，IDS识别nmap扫描一般都是根据UDP data区域填充的'C'字符串,ICMP填充的是0（正常windows下是a-z，Linux下是0-9）
alert udp $EXTERNAL_NET 10000: -> $HOME_NET 10000: (msg:"ET SCAN NMAP OS Detection Probe"; dsize:300; content:"CCCCCCCCCCCCCCCCCCCC"; fast_pattern:only; content:"CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC"; depth:255; content:"CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC"; within:45; classtype:attempted-recon; sid:2018489; rev:3; metadata:created_at 2014_05_20, updated_at 2014_05_20;)
https://raw.githubusercontent.com/nmap/nmap/master/osscan2.cc
static u8 patternbyte = 0x43; /* character 'C' */ 替换为 static u8 patternbyte = 0x46; /* character 'F' */
### nmap UA 修改
alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN Nmap Scripting Engine User-Agent Detected (Nmap Scripting Engine)"; flow:to_server,established; content:"Mozilla/5.0 (compatible|3b| Nmap Scripting Engine"; nocase; http_user_agent; depth:46; reference:url,doc.emergingthreats.net/2009358; classtype:web-application-attack; sid:2009358; rev:5; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
修改nselib/http.lua
USER_AGENT = stdnse.get_script_args('http.useragent') or "Mozilla/5.0 (compatible; )"
### TCP window 修改tcp window 窗口大小
nmap 默认扫描的tcp window size 大小是1024，将其修改为10240来绕过ids
alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sS window 1024"; fragbits:!D; dsize:0; flags:S,12; ack:0; window:1024; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2009582; classtype:attempted-recon; sid:2009582; rev:3; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
tcpip.cc:729: tcp->th_win = htons(1024); /* Who cares */
if (window)
tcp->th_win = htons(10240); /* Who cares */
### 修改nmap-service-probes
alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (msg:"ET SCAN NMAP SIP Version Detect OPTIONS Scan"; flow:established,to_server; content:"OPTIONS sip|3A|nm SIP/"; depth:19; classtype:attempted-recon; sid:2018317; rev:1; metadata:created_at 2014_03_25, updated_at 2014_03_25;)
-Probe TCP SIPOptions q|OPTIONS sip:nm SIP/2.0\r\nVia: SIP/2.0/TCP nm;branch=foo\r\nFrom: ;tag=root\r\nTo: \r\nCall-ID: 50000\r\nCSeq: 42 OPTIONS\r\nMax-Forwards: 70\r\nContent-Length: 0\r\nContact: \r\nAccept: application/sdp\r\n\r\n|
去掉OPTIONS sip
### 修改3389 cookie
nmap-service-probes
Probe TCP TerminalServerCookie q|\x03\0\0*%\xe0\0\0\0\0\0Cookie: mstshash=nmap\r\n\x01\0\x08\0\x03\0\0\0|
nselib/rdp.lua
local cookie = "mstshash=nmap"
### Zmap识别
很多网络扫描器会使用固定的tcp window或者ipid，这些都可以作为特征识别的一部分。
例如在使用zmap扫描时，通过抓包分析发现zmap使用了固定的IPID 54321以及固定的window值 65535，那么我可以写一个IDS规则来检测它
```
alert tcp any any -> any any (msg:"Detect ZMAP scan"; dsize:0; flags:S; window:65535; id:54321; threshold: type both, track by_src, count 60, seconds 60; sid:19010201; rev:1; metadata:created_at 2019_01_02, by al0ne;)
```
alert 是记录告警日志， tcp $EXTERNAL_NET any -> $HOME_NET any 这些对应着协议 源ip 源端口 方向 目标ip 目标端口，这里是匹配任意ip和任意端口，
dsize代表tcp data区大小扫描时没有附加其他数据所以为0，flags:S 是指tcp的flags为s即三次握手时syn请求，并且计算阀值60秒内出现60才告警
修改绕过
src/probe_modules/packet.c
```
tcp_header->th_win = htons(65535);
iph->ip_id = htons(54321);
```