2019年2月

使用osqueryd监控系统

0x01 说明

osquery初识主要是借由osqueryi的方式对osquery进行了一个基本的介绍。可以看到osqueryi是一个交互式的shell,我们可以很方便使用它进行测试,但是如果我们要将osquery投入实际使用,明显是osqueryd更加合适。本篇文章将详细地介绍osqueryd的使用。

0x02 osqueryd配置

如果使用osqueryi,我们可以通过osqueryi -audit_allow_config=true --audit_allow_sockets=true --audit_persist=true这样的方式传入设置。如果是osqueryd呢?其实我们安装好osquery之后,会以service的方式存在于系统中,同时可以利用systemctl的方式进行控制,其文件位于/usr/lib/systemd/system/osqueryd.service

[Unit]
Description=The osquery Daemon
After=network.service syslog.service

[Service]
TimeoutStartSec=0
EnvironmentFile=/etc/sysconfig/osqueryd
ExecStartPre=/bin/sh -c "if [ ! -f $FLAG_FILE ]; then touch $FLAG_FILE; fi"
ExecStartPre=/bin/sh -c "if [ -f $LOCAL_PIDFILE ]; then mv $LOCAL_PIDFILE $PIDFILE; fi"
ExecStart=/usr/bin/osqueryd \
  --flagfile $FLAG_FILE \
  --config_path $CONFIG_FILE
Restart=on-failure
KillMode=process
KillSignal=SIGTERM

[Install]
WantedBy=multi-user.target

启动方式就是ExecStart=/usr/bin/osqueryd --flagfile $FLAG_FILE --config_path $CONFIG_FILE,通过--flagfile--config_path的方式指定配置文件的路径。$FLAG_FILE和$CONFIG_FILE是在/etc/sysconfig/osqueryd中定义。

FLAG_FILE="/etc/osquery/osquery.flags"
CONFIG_FILE="/etc/osquery/osquery.conf"
LOCAL_PIDFILE="/var/osquery/osqueryd.pidfile"
PIDFILE="/var/run/osqueryd.pidfile"

默认的配置文件就是位于/etc/osquery/osquery.flags/etc/osquery/osquery.conf。当启动osqueryd时,如果不存在osquery.flagsosquery.conf会创建两个空文件,否则直接读取此文件的内容。其实osquery.conf可以认为是osquery.flags的超集,因为osquery.flags仅仅只是设置一些配置,而这些配置也同样可以在osquery.conf中实现,同时在osquery.conf中还可以配置osqueryd需要执行的SQL。所以接下来本文将仅仅只介绍osquery.conf的使用。

0x03 osquery.conf

osquery本身提供了一个osquery.conf的例子,其写法是一个JSON格式的文件,在这里我们将其简化一下。

{
  // Configure the daemon below:
  "options": {
    // Select the osquery config plugin.
    "config_plugin": "filesystem",

    // Select the osquery logging plugin.
    "logger_plugin": "filesystem",

    // The log directory stores info, warning, and errors.
    // If the daemon uses the 'filesystem' logging retriever then the log_dir
    // will also contain the query results.
    //"logger_path": "/var/log/osquery",

    // Set 'disable_logging' to true to prevent writing any info, warning, error
    // logs. If a logging plugin is selected it will still write query results.
    //"disable_logging": "false",

    // Splay the scheduled interval for queries.
    // This is very helpful to prevent system performance impact when scheduling
    // large numbers of queries that run a smaller or similar intervals.
    //"schedule_splay_percent": "10",

    // A filesystem path for disk-based backing storage used for events and
    // query results differentials. See also 'use_in_memory_database'.
    //"database_path": "/var/osquery/osquery.db",

    // Comma-delimited list of table names to be disabled.
    // This allows osquery to be launched without certain tables.
    //"disable_tables": "foo_bar,time",

    "utc": "true"
  },

  // Define a schedule of queries:
  "schedule": {
    // This is a simple example query that outputs basic system information.
    "system_info": {
      // The exact query to run.
      "query": "SELECT hostname, cpu_brand, physical_memory FROM system_info;",
      // The interval in seconds to run this query, not an exact interval.
      "interval": 3600
    }
  },

  // Decorators are normal queries that append data to every query.
  "decorators": {
    "load": [
      "SELECT uuid AS host_uuid FROM system_info;",
      "SELECT user AS username FROM logged_in_users ORDER BY time DESC LIMIT 1;"
    ]
  },
  "packs": {
    // "osquery-monitoring": "/usr/share/osquery/packs/osquery-monitoring.conf",
    ....
  }, 
}

osquery.conf文件大致可以分为4个部分。

  • options,配置选项,Command Line Flags基本上对所有的配置选项都进行了说明。其实osquery.flags所配置也是这个部分。这也是之前说的osquery.conf可以认为是osquery.flags的超集的原因;
  • schedule,配置SQL语句。因为osqueryd是以daemon的方式运行,所以需要通过在schedule中定义SQL语句使其定期执行返回结果;
  • decorators,中文意思是“装饰”。在decorators中也是定义了一系列的SQL语句,执行得到的结果会附加在是在执行schedule中的结果的后面;所以我们看到在decorators我们取的是uuid和登录的username
  • packs,就是一系列SQL语句的合集;

0x04 配置说明

上一节中对osquery.conf中的配置进了一个简单的说明,在本节中将详细说明。

options

  • options就是配置。Command Line Flags基本上对所有的配置选项都进行了说明。我们可以进行多种配置,有兴趣的可以自行研究。本节仅仅说明几个常用的配置;
  • config_plugin,配置选项是filesystem。如果是通过osquery.conf管理osquery就是采用filesystem,还有一种选项是tls(这一种主要是通过API的方式来配置osquery)。
  • logger_plugin,配置选项是filesystem,这也是osquery的默认值。根据Logger plugins,还可以配置tls,syslog (for POSIX,windows_event_log (for Windows),kinesis,firehose,kafka_producer
  • database_path,默认值是/var/osquery/osquery.db。因为osquery内部会使用到数据,所以配置此目录是osquery的数据库文件位置。
  • disable_logging,是配置设置osquery的结果是否需要保存到本地,这个配置其实和logger_plugin:filesystem有点重复。
  • hostIdentifier,相当于表示每个主机的标识,比如可以采用hostname作为标识。

schedule

schedule是osqeuryd用于写SQL语句的标签。其中的一个示例如下所示:

"system_info": {
    // The exact query to run.
    "query": "SELECT hostname, cpu_brand, physical_memory FROM system_info;",
    // The interval in seconds to run this query, not an exact interval.
    "interval": 3600
}

其中system_info是定义的一个SQL任务的名字,也是一个JSON格式。在其中可以进行多项设置,包括:

  1. query,定义需要执行的SQL语句;
  2. interval,定时执行的时间,示例中是3600,表示每隔3600秒执行一次;
  3. snapshot,可选选项,可以配置为snapshot:true。osquery默认执行的是增量模式,使用了snapshot则是快照模式。比如执行select * from processes;,osqeury每次产生的结果是相比上一次变化的结果;如果采用的是snapshot,则会显示所有的进程的,不会与之前的结果进行对比;
  4. removed,可选选项,默认值是true,用来设置是否记录actionremove的日志。

当然还有一些其他的不常用选项,如platformversionsharddescription等等。

更多关于schedule的介绍可以参考schedule

decorators

正如其注释Decorators are normal queries that append data to every query所说,Decorators会把他的执行结果添加到schedule中的sql语句执行结果中。所以根据其作用Decorators也不是必须存在的。。在本例中Decorators存在两条记录:

SELECT uuid AS host_uuid FROM system_info;
SELECT user AS username FROM logged_in_users ORDER BY time DESC LIMIT 1;
  1. SELECT uuid AS host_uuid FROM system_info,从system_info获取uuid作为标识符1;
  2. SELECT user AS username FROM logged_in_users ORDER BY time DESC LIMIT 1;,从logged_in_users选择user(其实查询的是用户名)的第一项作为标识符2;

当然可以在Decorators写多条语句作为标识符,但是感觉没有必要;

packs

packs就是打包的SQL语句的合集,本示例中使用的/usr/share/osquery/packs/osquery-monitoring.conf,这是官方提供的一个监控系统信息的SQL语句的集合;

{
  "queries": {
    "schedule": {
      "query": "select name, interval, executions, output_size, wall_time, (user_time/executions) as avg_user_time, (system_time/executions) as avg_system_time, average_memory, last_executed from osquery_schedule;",
      "interval": 7200,
      "removed": false,
      "blacklist": false,
      "version": "1.6.0",
      "description": "Report performance for every query within packs and the general schedule."
    },
    "events": {
      "query": "select name, publisher, type, subscriptions, events, active from osquery_events;",
      "interval": 86400,
      "removed": false,
      "blacklist": false,
      "version": "1.5.3",
      "description": "Report event publisher health and track event counters."
    },
    "osquery_info": {
      "query": "select i.*, p.resident_size, p.user_time, p.system_time, time.minutes as counter from osquery_info i, processes p, time where p.pid = i.pid;",
      "interval": 600,
      "removed": false,
      "blacklist": false,
      "version": "1.2.2",
      "description": "A heartbeat counter that reports general performance (CPU, memory) and version."
    }
  }
}

packs中的配置和schedule的配置方法并没有什么区别。我们在packs中查询到的信息包括:

  • osquery_schedule拿到osqueryd设置的schedule的配置信息;
  • osquery_events中拿到osqueryd所支持的所有的event
  • processesosquery_info中拿到进程相关的信息;

使用packs的好处是可以将一系列相同功能的SQL语句放置在同一个文件中;

0x05 运行osqueryd

当以上配置完毕之后,我们就可以通过sudo osqueryd的方式启动;如果我们设置logger_plugin:filesystem,那么日志就会落在本地/var/log/osquery下。此目录下包含了多个文件,每个文件分别记录不同的信息。

osqueryd.results.log,osqueryd的增量日志的信息都会写入到此文件中;保存结果的形式是JSON形式。示例如下:

{"name":"auditd_process_info","hostIdentifier":"localhost.localdomain","calendarTime":"Wed Oct 24 13:07:12 2018 UTC","unixTime":1540386432,"epoch":0,"counter":0,"decorations":{"host_uuid":"99264D56-9A4E-E593-0B4E-872FBF3CD064","username":"username"},"columns":{"atime":"1540380461","auid":"4294967295","btime":"0","cmdline":"awk { sum += $1 }; END { print 0+sum }","ctime":"1538239175","cwd":"\"/\"","egid":"0","euid":"0","gid":"0","mode":"0100755","mtime":"1498686768","owner_gid":"0","owner_uid":"0","parent":"4086","path":"/usr/bin/gawk","pid":"4090","time":"1540386418","uid":"0","uptime":"1630"},"action":"added"}
{"name":"auditd_process_info","hostIdentifier":"localhost.localdomain","calendarTime":"Wed Oct 24 13:07:12 2018 UTC","unixTime":1540386432,"epoch":0,"counter":0,"decorations":{"host_uuid":"99264D56-9A4E-E593-0B4E-872FBF3CD064","username":"username"},"columns":{"atime":"1540380461","auid":"4294967295","btime":"0","cmdline":"sleep 60","ctime":"1538240835","cwd":"\"/\"","egid":"0","euid":"0","gid":"0","mode":"0100755","mtime":"1523421302","owner_gid":"0","owner_uid":"0","parent":"741","path":"/usr/bin/sleep","pid":"4091","time":"1540386418","uid":"0","uptime":"1630"},"action":"added"}

其中的added表示的就是相当于上一次增加的进程信息;每一次执行的结果都是一条JSON记录;

squeryd.snapshots.log,记录的是osqueryd中使用snapshot:true标记的SQL语句执行结果;

{"snapshot":[{"header":"Defaults","rule_details":"!visiblepw"},{"header":"Defaults","rule_details":"always_set_home"},{"header":"Defaults","rule_details":"match_group_by_gid"},{"header":"Defaults","rule_details":"env_reset"},{"header":"Defaults","rule_details":"env_keep = \"COLORS DISPLAY HOSTNAME HISTSIZE KDEDIR LS_COLORS\""},{"header":"Defaults","rule_details":"env_keep += \"MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE\""},{"header":"Defaults","rule_details":"env_keep += \"LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES\""},{"header":"Defaults","rule_details":"env_keep += \"LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE\""},{"header":"Defaults","rule_details":"env_keep += \"LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY\""},{"header":"Defaults","rule_details":"secure_path = /sbin:/bin:/usr/sbin:/usr/bin"},{"header":"root","rule_details":"ALL=(ALL) ALL"},{"header":"%wheel","rule_details":"ALL=(ALL) ALL"}],"action":"snapshot","name":"sudoers","hostIdentifier":"localhost.localdomain","calendarTime":"Tue Oct  9 11:54:00 2018 UTC","unixTime":1539086040,"epoch":0,"counter":0,"decorations":{"host_uuid":"99264D56-9A4E-E593-0B4E-872FBF3CD064","username":"username"}}
{"snapshot":[{"header":"Defaults","rule_details":"!visiblepw"},{"header":"Defaults","rule_details":"always_set_home"},{"header":"Defaults","rule_details":"match_group_by_gid"},{"header":"Defaults","rule_details":"env_reset"},{"header":"Defaults","rule_details":"env_keep = \"COLORS DISPLAY HOSTNAME HISTSIZE KDEDIR LS_COLORS\""},{"header":"Defaults","rule_details":"env_keep += \"MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE\""},{"header":"Defaults","rule_details":"env_keep += \"LC_COLLATE LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES\""},{"header":"Defaults","rule_details":"env_keep += \"LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE\""},{"header":"Defaults","rule_details":"env_keep += \"LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY\""},{"header":"Defaults","rule_details":"secure_path = /sbin:/bin:/usr/sbin:/usr/bin"},{"header":"root","rule_details":"ALL=(ALL) ALL"},{"header":"%wheel","rule_details":"ALL=(ALL) ALL"}],"action":"snapshot","name":"sudoers","hostIdentifier":"localhost.localdomain","calendarTime":"Tue Oct  9 11:54:30 2018 UTC","unixTime":1539086070,"epoch":0,"counter":0,"decorations":{"host_uuid":"99264D56-9A4E-E593-0B4E-872FBF3CD064","username":"username"}}

由于snapshot是快照模式,所以即使两次结果相同也会全部显示出来;

osqueryd.INFO,记录osqueryd中正在运行的情况。示例如下:

Log file created at: 2018/11/22 17:06:06
Running on machine: osquery.origin
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
I1122 17:06:06.729902 22686 events.cpp:862] Event publisher not enabled: auditeventpublisher: Publisher disabled via configuration
I1122 17:06:06.730651 22686 events.cpp:862] Event publisher not enabled: syslog: Publisher disabled via configuration

osqueryd.WARNING,记录osquery的警告。示例如下:

Log file created at: 2018/10/09 19:53:45
Running on machine: localhost.localdomain
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
E1009 19:53:45.471046 104258 events.cpp:987] Requested unknown/failed event publisher: auditeventpublisher
E1009 19:53:45.471606 104259 events.cpp:987] Requested unknown/failed event publisher: inotify
E1009 19:53:45.471634 104260 events.cpp:987] Requested unknown/failed event publisher: syslog
E1009 19:53:45.471658 104261 events.cpp:987] Requested unknown/failed event publisher: udev

osqueryd.ERROR,记录的是osquery的错误信息。示例如下:

Log file created at: 2018/10/09 19:53:45
Running on machine: localhost.localdomain
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
E1009 19:53:45.471046 104258 events.cpp:987] Requested unknown/failed event publisher: auditeventpublisher
E1009 19:53:45.471606 104259 events.cpp:987] Requested unknown/failed event publisher: inotify
E1009 19:53:45.471634 104260 events.cpp:987] Requested unknown/failed event publisher: syslog
E1009 19:53:45.471658 104261 events.cpp:987] Requested unknown/failed event publisher: udev

在本例中错误信息和警告信息完全相同。在实际情况下,可能很多时候均不相同;

0x06 总结

本文主要是对osqueryd的常用配置进行了简要的说法。通过本文能够快速地利用上手osquery,由于篇幅的原因,有关osquery的很多东西没有介绍或者说明得很详细。官方的文档对osqueryd的配置已经说明得很是详尽了,如果对本文有任何的不解,可以去查阅相关的文档,也欢迎大家就相关问题与我讨论。

以上

osquery初识

0x01 说明

osquery是一个由FaceBook开源用于对系统进行查询、监控以及分析的一款软件。osquery对其的说明如下:

osquery exposes an operating system as a high-performance relational database. This allows you to write SQL-based queries to explore operating system data. With osquery, SQL tables represent abstract concepts such as running processes, loaded kernel modules, open network connections, browser plugins, hardware events or file hashes.

我们知道当你们在Linux中使用诸如pstopls -l等等命令的时候,可以发下其实他们的输出结果的格式都是很固定的很像一张表。或许是基于这样的想法,facebook开发了osquery。osquery将操作系统当作是一个高性能的关系型数据库。使用osquery运行我们能够使用类似于SQL语句的方式去查询数据库中的信息,比如正在运行的进程信息,加载的内核模块,网络连接,浏览器插件等等信息(一切查询的信息的粒度取决于osquery的实现粒度了)。

osquery也广泛地支持多个平台,包括MacOS、CentOS、Ubuntu、Windows 10以及FreeBSD,具体所支持的版本的信息也可以在osquery主页查看。除此之外,osquery的配套文档/网站也是一应俱全,包括主页Githubreadthedocsslack

本篇文章以CentOS为例说明Osquery的安装以及使用。

0x02 安装

主页上面提供了不同操作系统的安装包,我们下载CentOS对应的rpm文件即可。在本例中文件名是osquery-3.3.0-1.linux.x86_64.rpm,使用命令sudo yum install osquery-3.3.0-1.linux.x86_64.rpm安装。安装成功之后会出现:

Installed:
  osquery.x86_64 0:3.3.0-1.linux                                                                                                                                                             
Complete!

0x03 运行

osquery存在两种运行模式,分别是osqueryi(交互式模式)、osqueryd(后台进程模式)。

  • osqueryi,与osqueryd安全独立,不需要以管理员的身份运行,能够及时地查看当前操作系统的状态信息。
  • osqueryd,我们能够利用osqueryd执行定时查询记录操作系统的变化,例如在第一次执行和第二次执行之间的进程变化(增加/减少),osqueryd会将进程执行的结果保存(文件或者是直接打到kafka中)。osqueryd还会利用操作系统的API来记录文件目录的变化、硬件事件、网络行为的变化等等。osqueryd在Linux中是以系统服务的方式来运行。

为了便于演示,我们使用osqueyi来展示osquery强大的功能。我们直接在terminal中输入osqueryi即可进入到osqueryi的交互模式中(osqueryi采用的是sqlite的shell的语法,所以我们也可以使用在sqlite中的所有的内置函数)。

[user@localhost Desktop]$ osqueryi
Using a virtual database. Need help, type '.help'
osquery> .help
Welcome to the osquery shell. Please explore your OS!
You are connected to a transient 'in-memory' virtual database.

.all [TABLE]     Select all from a table
.bail ON|OFF     Stop after hitting an error
.echo ON|OFF     Turn command echo on or off
.exit            Exit this program
.features        List osquery's features and their statuses
.headers ON|OFF  Turn display of headers on or off
.help            Show this message
.mode MODE       Set output mode where MODE is one of:
                   csv      Comma-separated values
                   column   Left-aligned columns see .width
                   line     One value per line
                   list     Values delimited by .separator string
                   pretty   Pretty printed SQL results (default)
.nullvalue STR   Use STRING in place of NULL values
.print STR...    Print literal STRING
.quit            Exit this program
.schema [TABLE]  Show the CREATE statements
.separator STR   Change separator used by output mode
.socket          Show the osquery extensions socket path
.show            Show the current values for various settings
.summary         Alias for the show meta command
.tables [TABLE]  List names of tables
.width [NUM1]+   Set column widths for "column" mode
.timer ON|OFF      Turn the CPU timer measurement on or off

通过.help,我们能够查看在osqueryi模式下的一些基本操作。比如.exit表示退出osqueryi,.mode切换osqueryi的输出结果,.show展示目前osqueryi的配置信息,.tables展示在当前的操作系统中能够支持的所有的表名。.schema [TABLE]显示具体的表的结构信息。

osquery> .show
osquery - being built, with love, at Facebook

osquery 3.3.0
using SQLite 3.19.3

General settings:
     Flagfile: 
       Config: filesystem (/etc/osquery/osquery.conf)
       Logger: filesystem (/var/log/osquery/)
  Distributed: tls
     Database: ephemeral
   Extensions: core
       Socket: /home/xingjun/.osquery/shell.em

Shell settings:
         echo: off
      headers: on
         mode: pretty
    nullvalue: ""
       output: stdout
    separator: "|"
        width: 

Non-default flags/options:
  database_path: /home/xingjun/.osquery/shell.db
  disable_database: true
  disable_events: true
  disable_logging: true
  disable_watchdog: true
  extensions_socket: /home/xingjun/.osquery/shell.em
  hash_delay: 0
  logtostderr: true
  stderrthreshold: 3

可以看到设置包括常规设置(General settings)、shell设置(Shell settings)、非默认选项(Non-default flags/options)。在常规设置中主要是显示了各种配置文件的位置(配置文件/存储日志文件的路径)。 在shell设置中包括了是否需要表头信息(headers),显示方式(mode: pretty),分隔符(separator: "|")。

.table可以查看在当前操作系统中所支持的所有的表,虽然在schema中列出了所有的表(包括了win平台,MacOS平台,Linux平台)。但是具体到某一个平台上面是不会包含其他平台上的表。下方显示的就是我在CentOS7下显示的表。

osquery> .table
  => acpi_tables
  => apt_sources
  => arp_cache
  => augeas
  => authorized_keys
  => block_devices
  => carbon_black_info
  => carves
  => chrome_extensions
  => cpu_time
  => cpuid
  => crontab
...

.schema [TABLE]可以用于查看具体的表的结构信息。如下所示:

osquery> .schema users
CREATE TABLE users(`uid` BIGINT, `gid` BIGINT, `uid_signed` BIGINT, `gid_signed` BIGINT, `username` TEXT, `description` TEXT, `directory` TEXT, `shell` TEXT, `uuid` TEXT, `type` TEXT HIDDEN, PRIMARY KEY (`uid`, `username`)) WITHOUT ROWID;
osquery> .schema processes
CREATE TABLE processes(`pid` BIGINT, `name` TEXT, `path` TEXT, `cmdline` TEXT, `state` TEXT, `cwd` TEXT, `root` TEXT, `uid` BIGINT, `gid` BIGINT, `euid` BIGINT, `egid` BIGINT, `suid` BIGINT, `sgid` BIGINT, `on_disk` INTEGER, `wired_size` BIGINT, `resident_size` BIGINT, `total_size` BIGINT, `user_time` BIGINT, `system_time` BIGINT, `disk_bytes_read` BIGINT, `disk_bytes_written` BIGINT, `start_time` BIGINT, `parent` BIGINT, `pgroup` BIGINT, `threads` INTEGER, `nice` INTEGER, `is_elevated_token` INTEGER HIDDEN, `upid` BIGINT HIDDEN, `uppid` BIGINT HIDDEN, `cpu_type` INTEGER HIDDEN, `cpu_subtype` INTEGER HIDDEN, `phys_footprint` BIGINT HIDDEN, PRIMARY KEY (`pid`)) WITHOUT ROWID;

上面通过.schema查看usersprocesses表的信息,结果输出的是他们对应的DDL。

0x03 基本使用

在本章节中,将会演示使用osqueryi来实时查询操作系统中的信息(为了方便展示查询结果使用的是.mode line模式)。

查看系统信息

osquery> select * from system_info;
          hostname = localhost
              uuid = 4ee0ad05-c2b2-47ce-aea1-c307e421fa88
          cpu_type = x86_64
       cpu_subtype = 158
         cpu_brand = Intel(R) Core(TM) i5-8400 CPU @ 2.80GHz
cpu_physical_cores = 1
 cpu_logical_cores = 1
     cpu_microcode = 0x84
   physical_memory = 2924228608
   hardware_vendor = 
    hardware_model = 
  hardware_version = 
   hardware_serial = 
     computer_name = localhost.localdomain
    local_hostname = localhost

查询的结果包括了CPU的型号,核数,内存大小,计算机名称等等;

查看OS版本

osquery> select * from os_version;
         name = CentOS Linux
      version = CentOS Linux release 7.4.1708 (Core)
        major = 7
        minor = 4
        patch = 1708
        build = 
     platform = rhel
platform_like = rhel
     codename =

以看到我的本机的操作系统的版本是CentOS Linux release 7.4.1708 (Core)

查看内核信息版本

osquery> SELECT * FROM kernel_info;
  version = 3.10.0-693.el7.x86_64
arguments = ro crashkernel=auto rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet LANG=en_US.UTF-8
     path = /vmlinuz-3.10.0-693.el7.x86_64
   device = /dev/mapper/centos-root

osquery> SELECT * FROM kernel_modules LIMIT 3;
   name = tcp_lp
   size = 12663
used_by = -
 status = Live
address = 0xffffffffc06cf000

   name = fuse
   size = 91874
used_by = -
 status = Live
address = 0xffffffffc06ae000

   name = xt_CHECKSUM
   size = 12549
used_by = -
 status = Live
address = 0xffffffffc06a9000

查询repo和pkg信息

osquery提供查询系统中的repo和okg相关信息的表。在Ubuntu中对应的是apt相关的包信息,在Centos中对应的是yum相关的包信息。本例均以yum包为例进行说明

osquery> SELECT * FROM yum_sources  limit 2;
    name = CentOS-$releasever - Base
 baseurl = 
 enabled = 
gpgcheck = 1
  gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

    name = CentOS-$releasever - Updates
 baseurl = 
 enabled = 
gpgcheck = 1
  gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

我们可以直接利用yum_sources来查看操作系统的yum源相关的信息。

osquery> SELECT name, version FROM rpm_packages order by name limit 3;
   name = GConf2
version = 3.2.6

   name = GeoIP
version = 1.5.0

   name = ModemManager
version = 1.6.0

利用rpm_packages查看系统中已经安装的rpm包信息。我们也可以通过name对我们需要查询的包进行过滤,如下:

osquery> SELECT name, version FROM rpm_packages where name="osquery";
   name = osquery
version = 3.3.0

挂载信息

我们可以使用mounts表来查询系统中的具体的驱动信息。例如我们可以如下的SQL语句进行查询:

SELECT * FROM mounts;
SELECT device, path, type, inodes_free, flags FROM mounts;

我们也可以使用where语句查询摸一个具体的驱动信息,例如ext4或者是tmpfs信息。如下:

osquery> SELECT device, path, type, inodes_free, flags FROM mounts WHERE type="ext4";
osquery> SELECT device, path, type, inodes_free, flags FROM mounts WHERE type="tmpfs";
     device = tmpfs
       path = /dev/shm
       type = tmpfs
inodes_free = 356960
      flags = rw,seclabel,nosuid,nodev

     device = tmpfs
       path = /run
       type = tmpfs
inodes_free = 356386
      flags = rw,seclabel,nosuid,nodev,mode=755

     device = tmpfs
       path = /sys/fs/cgroup
       type = tmpfs
inodes_free = 356945
      flags = ro,seclabel,nosuid,nodev,noexec,mode=755

     device = tmpfs
       path = /run/user/42
       type = tmpfs
inodes_free = 356955
      flags = rw,seclabel,nosuid,nodev,relatime,size=285572k,mode=700,uid=42,gid=42

     device = tmpfs
       path = /run/user/1000
       type = tmpfs
inodes_free = 356939
      flags = rw,seclabel,nosuid,nodev,relatime,size=285572k,mode=700,uid=1000,gid=1000

内存信息

使用memory_info查看内存信息,如下:

osquery> select * from memory_info;
memory_total = 2924228608
 memory_free = 996024320
     buffers = 4280320
      cached = 899137536
 swap_cached = 0
      active = 985657344
    inactive = 629919744
  swap_total = 2684350464
   swap_free = 2684350464

网卡信息

使用interface_addresses查看网卡信息,如下:

osquery> SELECT * FROM interface_addresses;
     interface = lo
       address = 127.0.0.1
          mask = 255.0.0.0
     broadcast = 
point_to_point = 127.0.0.1
          type = 

     interface = virbr0
       address = 192.168.122.1
          mask = 255.255.255.0
     broadcast = 192.168.122.255
point_to_point = 
          type = 

     interface = lo
       address = ::1
          mask = ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
     broadcast = 
point_to_point = 
          type =

还可以使用interface_details查看更加具体的网卡信息。

SELECT * FROM interface_details;
SELECT interface, mac, ipackets, opackets, ibytes, obytes FROM interface_details;

查询结果如下

osquery> SELECT * FROM interface_details;
  interface = lo
        mac = 00:00:00:00:00:00
       type = 4
        mtu = 65536
     metric = 0
      flags = 65609
   ipackets = 688
   opackets = 688
     ibytes = 59792
     obytes = 59792
    ierrors = 0
    oerrors = 0
     idrops = 0
     odrops = 0
 collisions = 0
last_change = -1
 link_speed = 
   pci_slot = 
    ....

系统启动时间

osquery> select * from uptime;
         days = 0
        hours = 2
      minutes = 23
      seconds = 51
total_seconds = 8631

查询用户信息

osquery提供了多个表用于查询用户的信息,包括使用users表检索系统中所有的用户,使用last表查看用户上次登录的信息,使用logged_in_user查询具有活动shell的用户信息。

使用select * from users查看所有用户信息,使用类似于uid>1000的方式过滤用户。

osquery> select * from users where uid>1000;
        uid = 65534
        gid = 65534
 uid_signed = 65534
 gid_signed = 65534
   username = nfsnobody
description = Anonymous NFS User
  directory = /var/lib/nfs
      shell = /sbin/nologin
       uuid =

我们可以使用last表查询最终的登录信息,如SELECT * FROM last;。对于普通用户来说,其type值为7。那么我们的查询条件如下:

osquery> SELECT * FROM last where type=7;
username = user
     tty = :0
     pid = 12776
    type = 7
    time = 1539882439
    host = :0

username = user
     tty = pts/0
     pid = 13754
    type = 7
    time = 1539882466
    host = :0

其中的time是时间戳类型,转换为具体的日期之后就可以看到具体的登录时间了。

使用SELECT * FROM logged_in_users;查看当前已经登录的用户信息。

防火墙信息

我们可以使用iptables来查看具体的防火墙信息,如select * from iptables;,也可以进行过滤查询具体的防火墙信息。如SELECT chain, policy, src_ip, dst_ip FROM iptables WHERE chain="POSTROUTING" order by src_ip;

进程信息

我们可以使用processes来查询系统上进程的信息,包括pid,name,path,command等等。
可以使用select * from processes;或者查看具体的某几项信息,select pid,name,path,cmdline from processes;

osquery> select pid,name,path,cmdline from processes limit 2;
    pid = 1
   name = systemd
   path = 
cmdline = /usr/lib/systemd/systemd --switched-root --system --deserialize 21

    pid = 10
   name = watchdog/0
   path = 
cmdline =

检查计划任务

我们可以使用crontab来检查系统中的计划任务。

osquery> select * from crontab;
       event = 
      minute = 01
        hour = *
day_of_month = *
       month = *
 day_of_week = *
     command = root run-parts /etc/cron.hourly
        path = /etc/cron.d/0hourly

       event = 
      minute = 0
        hour = 1
day_of_month = *
       month = *
 day_of_week = Sun
     command = root /usr/sbin/raid-check
        path = /etc/cron.d/raid-check

其他

在Linux中还存在其他很多的表能够帮助我们更好地进行入侵检测相关的工作,包括process_eventssocket_eventsprocess_open_sockets等等,这些表可供我们进行入侵检测的确认工作。至于这些表的工作原理,有待阅读osquery的源代码进行进一步分析。

0x04 总结

本文主要是对Osquery的基础功能进行了介绍。Oquery的强大功能需要进一步地挖掘和发现。总体来说,Osquery将操作系统中的信息抽象成为一张张表,对于进行基线检查,系统监控是一个非常优雅的方式。当然由于Osquery在这方面的优势,也可以考虑将其作为HIDS的客户端,但是如果HIDS仅仅只有Osquery也显然是不够的。

以上