Snort3 インストール
RockyLinux8はSnortリポジトリがありませんので、ソースコードからSnort3をビルド、コンパイルしてインストールします
事前準備
①ビルドとインストールに必要なビルドツールと依存関係のあるライブラリーをインストール。
EPELをインストールし、Powertoolsリポジトリを有効にします。
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# dnf install epel-release # dnf config-manager --set-enabled powertools |
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# dnf install bison flex libtool nghttp2 libnghttp2-devel libpcap-devel pcre-devel openssl-devel libdnet-devel libtirpc-devel git gcc-c++ libunwind-devel cmake hwloc-devel luajit-devel xz-devel libnfnetlink-devel libmnl-devel libnetfilter_queue-devel uuid-devel libsafec-devel -y |
②SNORT3のインストール作業ディレクトリー作成
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# mkdir snort_src && cd snort_src |
③DAQのダウンロード、インストール
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# git clone https://github.com/snort3/libdaq.git # cd libdaq # ./bootstrap # ./configure # make # make install |
④メモリ使用量の増加時の速度が向上のためgperftoolsインストール
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# cd ~/snort_src # wget https://github.com/gperftools/gperftools/releases/download/gperftools-2.9.1/gperftools-2.9.1.tar.gz # tar xzf gperftools-2.9.1.tar.gz # cd gperftools-2.9.1/ # ./configure # make # make install |
Snort3 ダウンロード、インストール
①Snort3をダウンロードしてインストール
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# cd ~/snort_src # wget https://github.com/snort3/snort3/archive/refs/tags/3.1.31.0.tar.gz # tar xzf 3.1.31.0.tar.gz # cd snort3-3.1.31.0 # ./configure_cmake.sh --prefix=/usr/local --enable-tcmalloc # cd build # make # make install |
②共有ライブラリを更新
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# ln -s /usr/local/lib/libtcmalloc.so.4 /lib/ # ln -s /usr/local/lib/libdaq.so.3 /lib/ # ldconfig |
Snort3を構成する
①ネットワークインターフェイスカードを構成
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# ip link set dev ens160 promisc on # ip add sh ens160 2: ens160: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 00:0c:29:3f:48:ad brd ff:ff:ff:ff:ff:ff inet 192.168.11.83/24 brd 192.168.11.255 scope global noprefixroute ens160 valid_lft forever preferred_lft forever |
Snortが1518バイトを超える大きなパケットを切り捨てないよう、インターフェイスオフロードを無効にする
現状の確認
現状の確認
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# ethtool -k ens160 | grep receive-offload generic-receive-offload: on large-receive-offload: on |
GROがonになっているのてこれを無効にする
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# ethtool -K ens160 gro off lro off |
システムの再起動後も変更が反映するように、systemdサービスを作成して有効にする
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# vi /etc/systemd/system/snort3-promisc.service |
snort3-promisc.serviceの内容
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[Unit] Description=Set Snort 3 NIC in promiscuous mode and Disable GRO, LRO on boot After=network.target [Service] Type=oneshot ExecStart=/usr/sbin/ip link set dev ens160 promisc on ExecStart=/usr/sbin/ethtool -K ens160 gro off lro off TimeoutStartSec=0 RemainAfterExit=yes [Install] WantedBy=default.target |
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# systemctl daemon-reload # systemctl enable --now snort3-promisc.service |
②ルールセットを構成
今回はコミュニティールールをセットします
今回はコミュニティールールをセットします
ルールディレクトリを作成
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# mkdir /usr/local/etc/rules |
③Snort3コミュニティルールをダウンロードしてルールディレクトリに保存
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# wget -qO- https://www.snort.org/downloads/community/snort3-community-rules.tar.gz | tar xz -C /usr/local/etc/rules/ # ls -1 /usr/local/etc/rules/snort3-community-rules/ AUTHORS LICENSE sid-msg.map snort3-community.rules VRT-License.txt |
④構成ファイルを編集
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# vi /usr/local/etc/snort/snort.lua # 24行目 : 自ネットワークに変更 HOME_NET = '192.168.11.0/24' # 24行目 : 変更 EXTERNAL_NET = '!$HOME_NET' |
⑤ルールへのパスを更新
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# vi /usr/local/etc/snort/snort.lua # 193行目あたり : 追記 ips = { -- use this to enable decoder and inspector alerts --enable_builtin_rules = true,-- use include for rules files; be sure to set your path -- note that rules files can include other rules files -- (see also related path vars at the top of snort_defaults.lua) variables = default_variables, rules = [[ include $RULE_PATH/snort3-community-rules/snort3-community.rules ]] } |
⑥SnortOpenAppIDのインストール
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# wget https://www.snort.org/downloads/openappid/23020 -O OpenAppId-23020.tgz # tar -xzvf OpenAppId-23020.tgz # cp -R odp /usr/local/lib/ |
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# vi /usr/local/etc/snort/snort.lua # 101行目あたり : 追記 appid = { -- appid requires this to use appids in rules --app_detector_dir = 'directory to load appid detectors from' app_detector_dir = '/usr/local/lib', log_stats = true, } |
⑦ログディレクトリー作成
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# mkdir /var/log/snort |
⑧構成のチェック
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# snort -c /usr/local/etc/snort/snort.lua --daq-dir /usr/local/lib/daq |
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-------------------------------------------------- o")~ Snort++ 3.1.28.0 -------------------------------------------------- Loading /usr/local/etc/snort/snort.lua: Loading snort_defaults.lua: Finished snort_defaults.lua: Loading file_magic.lua: Finished file_magic.lua: ssh hosts host_cache pop so_proxy stream_tcp mms smtp gtp_inspect packets dce_http_proxy stream_icmp normalizer ips network binder wizard appid file_id stream_udp http2_inspect http_inspect ftp_data search_engine ftp_server port_scan dce_http_server dce_smb dce_tcp netflow iec104 cip telnet ssl sip rpc_decode modbus host_tracker stream_user stream_ip process back_orifice classifications dnp3 active trace ftp_client decode alerts stream daq references arp_spoof output dns dce_udp imap file_policy s7commplus stream_file Finished /usr/local/etc/snort/snort.lua: Loading ips.rules: Loading ../rules/snort3-community-rules/snort3-community.rules: Finished ../rules/snort3-community-rules/snort3-community.rules: Finished ips.rules: -------------------------------------------------- ips policies rule stats id loaded shared enabled file 0 4024 0 4024 /usr/local/etc/snort/snort.lua -------------------------------------------------- rule counts total rules loaded: 4024 text rules: 4024 option chains: 4024 chain headers: 324 flowbits: 48 flowbits not checked: 23 -------------------------------------------------- port rule counts tcp udp icmp ip any 473 58 147 22 src 177 17 0 0 dst 787 154 0 0 both 6 11 0 0 total 1443 240 147 22 -------------------------------------------------- service rule counts to-srv to-cli dcerpc: 7 4 dhcp: 2 2 dns: 28 7 ftp: 90 4 ftp-data: 1 97 http: 2077 256 http2: 2077 256 imap: 35 118 irc: 5 2 kerberos: 7 0 ldap: 0 1 mysql: 3 0 netbios-dgm: 1 1 netbios-ns: 4 3 netbios-ssn: 73 17 nntp: 2 0 pop3: 23 118 rdp: 5 0 sip: 5 5 smtp: 130 2 snmp: 18 7 ssdp: 3 0 ssl: 18 40 sunrpc: 68 4 telnet: 12 6 tftp: 1 0 wins: 1 0 total: 4696 950 -------------------------------------------------- fast pattern groups src: 59 dst: 158 any: 4 to_server: 47 to_client: 34 -------------------------------------------------- search engine instances: 302 patterns: 7518 pattern chars: 121768 num states: 82296 num match states: 7149 memory scale: MB total memory: 2.58334 pattern memory: 0.402628 match list memory: 0.914368 transition memory: 1.22948 fast pattern only: 4963 -------------------------------------------------- pcap DAQ configured to passive. Snort successfully validated the configuration (with 0 warnings). o")~ Snort exiting |
⑨ローカルルールを作成
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# vi /usr/local/etc/rules/local.rules 以下を記入 alert icmp any any -> $HOME_NET any (msg:"ICMP connection test"; sid:1000001; rev:1;) |
テスト実行
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# snort -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/rules/local.rules -i ens160 -A alert_fast -s 65535 -k none --daq-dir /usr/local/lib/daq |
同じネットワーク内の別のPCからサーバーにpingすると、コンソール画面に以下のように表示される
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++ [0] ens160 06/20-17:58:56.092420 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.20 -> 192.168.11.83 06/20-17:58:56.092462 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.83 -> 192.168.11.20 06/20-17:58:57.104416 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.20 -> 192.168.11.83 06/20-17:58:57.104442 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.83 -> 192.168.11.20 06/20-17:58:58.109416 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.20 -> 192.168.11.83 06/20-17:58:58.109443 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.83 -> 192.168.11.20 06/20-17:58:59.115335 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.20 -> 192.168.11.83 06/20-17:58:59.115376 [**] [1:1000001:1] "ICMP connection test" [**] [Priority: 0] [AppID: ICMP] {ICMP} 192.168.11.83 -> 192.168.11.20 |
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# vi /usr/local/etc/snort/snort.lua # 255行目 : コメント解除して追記 -- event logging -- you can enable with defaults from the command line with -A -- uncomment below to set non-default configs --alert_csv = { } alert_fast = { file = true, packet = false, limit = 10, } --alert_full = { } --alert_sfsocket = { } --alert_syslog = { } --unified2 = { } |
ログディレクトリーにalert_fast.txt ファイルが作成される
構成をチェック
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# snort -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/rules/local.rules -i ens160 -s 65535 -k none -l /var/log/snort/ --daq-dir /usr/local/lib/daq |
再度、同じネットワーク内の別のPCからサーバーにpingすると今度はコンソール画面には何も表示されないが
ログディレクトリを確認すると、 alert_fast.txt ファイルが作成されました
alert_fast.txt ファイルを確認するには
ログディレクトリを確認すると、 alert_fast.txt ファイルが作成されました
alert_fast.txt ファイルを確認するには
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# tail -f /var/log/snort/alert_fast.txt |
⑪ローカルルールをsnort.luaに含める
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# vi /usr/local/etc/snort/snort.lua # 197行目 : 追記 ips = { -- use this to enable decoder and inspector alerts --enable_builtin_rules = true,-- use include for rules files; be sure to set your path -- note that rules files can include other rules files -- (see also related path vars at the top of snort_defaults.lua) variables = default_variables, rules = [[ include $RULE_PATH/snort3-community-rules/snort3-community.rules include $RULE_PATH/local.rules ]] } |
バックグラウンドでSnortを実行
①Snortの非ログインシステムユーザーアカウントを作成
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# useradd -r -s /usr/sbin/nologin -M -c SNORT_IDS snort |
②systemdサービスユニットを作成
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# vi /etc/systemd/system/snort3.service |
snort3.serviceの内容
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[Unit] Description=Snort Daemon After=syslog.target network.target [Service] Type=simple ExecStart=/usr/local/bin/snort -c /usr/local/etc/snort/snort.lua -s 65535 -k none -l /var/log/snort -D -i ens160 -m 0x1b -u snort -g snort --daq-dir /usr/local/lib/daq ExecStop=/bin/kill -9 $MAINPID [Install] WantedBy=multi-user.target |
再起動
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# systemctl daemon-reload |
ログファイルの所有権と権限を設定
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# chmod -R 5775 /var/log/snort # chown -R snort:snort /var/log/snort |
③Snortを起動し、システム起動時に実行できるようにする
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# systemctl enable --now snort3 Created symlink /etc/systemd/system/multi-user.target.wants/snort3.service → /etc/systemd/system/snort3.service. |
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# systemctl status snort3 ● snort3.service - Snort Daemon Loaded: loaded (/etc/systemd/system/snort3.service; enabled; vendor preset> Active: active (running) since Mon 2022-06-20 11:05:53 JST; 26s ago Main PID: 3220 (snort) Tasks: 2 (limit: 4538) Memory: 234.6M CPU: 910ms CGroup: /system.slice/snort3.service mq3220 /usr/local/bin/snort -c /usr/local/etc/snort/snort.lua -s 6>Jun 20 11:05:53 ubuntu22 systemd[1]: Started Snort Daemon. |
