nmap扫描

nmap简介

Nmap(Network Mapper)是一个开源的网络扫描和安全审计工具,广泛用于网络发现和安全评估。它由Gordon Lyon(Fyodor)开发,最初发布于1997年。Nmap的主要功能是扫描目标主机或网络,检测开放端口、运行的服务、操作系统版本以及潜在的漏洞。它被网络管理员和安全研究人员广泛使用,既可以用于合法的网络管理,也可以用于渗透测试。

Nmap支持多种扫描技术(如TCP SYN扫描、UDP扫描、Ping扫描等),并提供灵活的选项来满足不同需求。它的输出结果详细且易于解析,常用于生成网络拓扑图或识别安全弱点。

主要功能

  1. 主机发现:确定网络中哪些主机处于活动状态。
  2. 端口扫描:检测目标主机上哪些端口是开放的。
  3. 服务检测:识别开放端口上运行的具体服务及其版本。
  4. 操作系统检测:猜测目标主机的操作系统类型和版本。
  5. 脚本引擎(NSE):通过Nmap Scripting Engine执行自定义脚本,用于漏洞检测或高级信息收集。
➜  ~ nmap --help
Nmap 7.95 ( https://nmap.org )
Usage: nmap [Scan Type(s)] [Options] {target specification}

TARGET SPECIFICATION: (目标主机定义)
  Can pass hostnames, IP addresses, networks, etc.
  Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.0-255.1-254
  -iL <inputfilename>: Input from list of hosts/networks   ### 基于读取文件形式扫描
  -iR <num hosts>: Choose random targets
  --exclude <host1[,host2][,host3],...>: Exclude hosts/networks
  --excludefile <exclude_file>: Exclude list from file

HOST DISCOVERY:(主机发现)
  -sL: List Scan - simply list targets to scan
  -sn: Ping Scan - disable port scan  ### 存活检测
  -Pn: Treat all hosts as online -- skip host discovery
  -PS/PA/PU/PY[portlist]: TCP SYN, TCP ACK, UDP or SCTP discovery to given ports
  -PE/PP/PM: ICMP echo, timestamp, and netmask request discovery probes
  -PO[protocol list]: IP Protocol Ping
  -n/-R: Never do DNS resolution/Always resolve [default: sometimes]
  --dns-servers <serv1[,serv2],...>: Specify custom DNS servers
  --system-dns: Use OS's DNS resolver
  --traceroute: Trace hop path to each host

SCAN TECHNIQUES:(扫描技术)
  -sS/sT/sA/sW/sM: TCP SYN/Connect()/ACK/Window/Maimon scans
  -sU: UDP Scan
  -sN/sF/sX: TCP Null, FIN, and Xmas scans
  --scanflags <flags>: Customize TCP scan flags
  -sI <zombie host[:probeport]>: Idle scan
  -sY/sZ: SCTP INIT/COOKIE-ECHO scans
  -sO: IP protocol scan
  -b <FTP relay host>: FTP bounce scan

PORT SPECIFICATION AND SCAN ORDER:(端口扫描)
  -p <port ranges>: Only scan specified ports
    Ex: -p22; -p1-65535; -p U:53,111,137,T:21-25,80,139,8080,S:9
  --exclude-ports <port ranges>: Exclude the specified ports from scanning
  -F: Fast mode - Scan fewer ports than the default scan
  -r: Scan ports sequentially - don't randomize
  --top-ports <number>: Scan <number> most common ports
  --port-ratio <ratio>: Scan ports more common than <ratio>

SERVICE/VERSION DETECTION:
  -sV: Probe open ports to determine service/version info
  --version-intensity <level>: Set from 0 (light) to 9 (try all probes)
  --version-light: Limit to most likely probes (intensity 2)
  --version-all: Try every single probe (intensity 9)
  --version-trace: Show detailed version scan activity (for debugging)

SCRIPT SCAN:
  -sC: equivalent to --script=default
  --script=<Lua scripts>: <Lua scripts> is a comma separated list of
           directories, script-files or script-categories
  --script-args=<n1=v1,[n2=v2,...]>: provide arguments to scripts
  --script-args-file=filename: provide NSE script args in a file
  --script-trace: Show all data sent and received
  --script-updatedb: Update the script database.
  --script-help=<Lua scripts>: Show help about scripts.
           <Lua scripts> is a comma-separated list of script-files or
           script-categories.

OS DETECTION:
  -O: Enable OS detection
  --osscan-limit: Limit OS detection to promising targets
  --osscan-guess: Guess OS more aggressively

TIMING AND PERFORMANCE:
  Options which take <time> are in seconds, or append 'ms' (milliseconds),
  's' (seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m).
  -T<0-5>: Set timing template (higher is faster)
  --min-hostgroup/max-hostgroup <size>: Parallel host scan group sizes
  --min-parallelism/max-parallelism <numprobes>: Probe parallelization
  --min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout <time>: Specifies
      probe round trip time.
  --max-retries <tries>: Caps number of port scan probe retransmissions.
  --host-timeout <time>: Give up on target after this long
  --scan-delay/--max-scan-delay <time>: Adjust delay between probes
  --min-rate <number>: Send packets no slower than <number> per second
  --max-rate <number>: Send packets no faster than <number> per second
FIREWALL/IDS EVASION AND SPOOFING:
  -f; --mtu <val>: fragment packets (optionally w/given MTU)
  -D <decoy1,decoy2[,ME],...>: Cloak a scan with decoys
  -S <IP_Address>: Spoof source address
  -e <iface>: Use specified interface
  -g/--source-port <portnum>: Use given port number
  --proxies <url1,[url2],...>: Relay connections through HTTP/SOCKS4 proxies
  --data <hex string>: Append a custom payload to sent packets
  --data-string <string>: Append a custom ASCII string to sent packets
  --data-length <num>: Append random data to sent packets
  --ip-options <options>: Send packets with specified ip options
  --ttl <val>: Set IP time-to-live field
  --spoof-mac <mac address/prefix/vendor name>: Spoof your MAC address
  --badsum: Send packets with a bogus TCP/UDP/SCTP checksum
OUTPUT:
  -oN/-oX/-oS/-oG <file>: Output scan in normal, XML, s|<rIpt kIddi3,
     and Grepable format, respectively, to the given filename.
  -oA <basename>: Output in the three major formats at once
  -v: Increase verbosity level (use -vv or more for greater effect)
  -d: Increase debugging level (use -dd or more for greater effect)
  --reason: Display the reason a port is in a particular state
  --open: Only show open (or possibly open) ports
  --packet-trace: Show all packets sent and received
  --iflist: Print host interfaces and routes (for debugging)
  --append-output: Append to rather than clobber specified output files
  --resume <filename>: Resume an aborted scan
  --noninteractive: Disable runtime interactions via keyboard
  --stylesheet <path/URL>: XSL stylesheet to transform XML output to HTML
  --webxml: Reference stylesheet from Nmap.Org for more portable XML
  --no-stylesheet: Prevent associating of XSL stylesheet w/XML output
MISC:
  -6: Enable IPv6 scanning
  -A: Enable OS detection, version detection, script scanning, and traceroute
  --datadir <dirname>: Specify custom Nmap data file location
  --send-eth/--send-ip: Send using raw ethernet frames or IP packets
  --privileged: Assume that the user is fully privileged
  --unprivileged: Assume the user lacks raw socket privileges
  -V: Print version number
  -h: Print this help summary page.
EXAMPLES:
  nmap -v -A scanme.nmap.org
  nmap -v -sn 192.168.0.0/16 10.0.0.0/8
  nmap -v -iR 10000 -Pn -p 80
SEE THE MAN PAGE (https://nmap.org/book/man.html) FOR MORE OPTIONS AND EXAMPLES
➜  ~ 

使用示例

以下是一些常见的Nmap命令及其用途,假设你有合法权限扫描目标网络(未经授权扫描可能违法):

1. 基本主机发现

1
nmap -sn 192.168.1.0/24
  • 说明:扫描局域网段192.168.1.0-255,仅检测哪些主机在线(不扫描端口)。
  • 输出示例
    Host is up (0.0023s latency).
    Nmap scan report for 192.168.1.1
    Host is up (0.0018s latency).
    Nmap scan report for 192.168.1.100

2. 端口扫描

1
nmap 192.168.1.100
  • 说明:扫描目标IP192.168.1.100的默认1000个常见端口。
  • 输出示例
    PORT STATE SERVICE
    22/tcp open ssh
    80/tcp open http
    443/tcp open https

3. 指定端口扫描

1
nmap -p 22,80,443 192.168.1.100
  • 说明:仅扫描目标的22(SSH)、80(HTTP)和443(HTTPS)端口。
  • 输出示例
    PORT STATE SERVICE
    22/tcp open ssh
    80/tcp closed http
    443/tcp open https

4. 服务和版本检测

1
nmap -sV 192.168.1.100
  • 说明:扫描开放端口并检测服务版本。
  • 输出示例
    PORT STATE SERVICE VERSION
    22/tcp open ssh OpenSSH 8.9p1
    80/tcp open http Apache httpd 2.4.52

5. 操作系统检测

1
nmap -O 192.168.1.100
  • 说明:扫描端口并尝试识别操作系统。
  • 输出示例
    OS details: Linux 5.10 - 5.15

6. 隐秘扫描(SYN扫描)

1
nmap -sS 192.168.1.100
  • 说明:使用TCP SYN扫描,速度快且不易被目标检测到。
  • 输出示例
    PORT STATE SERVICE
    22/tcp open ssh
    80/tcp open http

7. 扫描并使用脚本

1
nmap --script vuln 192.168.1.100
  • 说明:使用Nmap脚本引擎检测目标是否存在已知漏洞。
  • 输出示例
    PORT STATE SERVICE
    80/tcp open http
    | http-vuln-cve2017-5638: VULNERABLE
    | Apache Struts vulnerability

注意事项

  • 权限:在公共网络或未经授权的系统上使用Nmap可能违反法律或服务条款,仅在有明确权限的情况下使用。
  • 参数:Nmap选项非常丰富,可以通过nmap --help查看更多用法。
  • 性能:扫描大型网络时,可用-T4-T5加速,但可能增加被检测的风险。