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随着开源产品的越来越盛行,作为一个Linux运维工程师,能够清晰地鉴别异常机器是否已经被入侵了显得至关重要,个人结合自己的工作经历,整理了几种常见的机器被黑情况供参考

背景信息:以下情况是在CentOS 6.9的系统中查看的,其它Linux发行版类似

1.入侵者可能会删除机器的日志信息,可以查看日志信息是否还存在或者是否被清空,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="98eaf7f7ecd8f0f4f5fbfdf6aea1f6ab">[email protected]</a> ~]# ll -h /var/log/*
-rw-------. 1 root root 2.6K Jul 7 18:31 /var/log/anaconda.ifcfg.log
-rw-------. 1 root root 23K Jul 7 18:31 /var/log/anaconda.log
-rw-------. 1 root root 26K Jul 7 18:31 /var/log/anaconda.program.log
-rw-------. 1 root root 63K Jul 7 18:31 /var/log/anaconda.storage.log
[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="493b26263d092125242a2c277f70277a">[email protected]</a> ~]# du -sh /var/log/*
8.0K /var/log/anaconda
4.0K /var/log/anaconda.ifcfg.log
24K /var/log/anaconda.log
28K /var/log/anaconda.program.log
64K /var/log/anaconda.storage.log

2.入侵者可能创建一个新的存放用户名及密码文件,可以查看/etc/passwd及/etc/shadow文件,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="80f2efeff4c0e8ecede3e5eeb6b9eeb3">[email protected]</a> ~]# ll /etc/pass*
-rw-r--r--. 1 root root 1373 Sep 15 11:36 /etc/passwd
-rw-r--r--. 1 root root 1373 Sep 15 11:36 /etc/passwd-
[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="c8baa7a7bc88a0a4a5abada6fef1a6fb">[email protected]</a> ~]# ll /etc/sha*
----------. 1 root root 816 Sep 15 11:36 /etc/shadow
----------. 1 root root 718 Sep 15 11:36 /etc/shadow-

3.入侵者可能修改用户名及密码文件,可以查看/etc/passwd及/etc/shadow文件内容进行鉴别,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="9ceef3f3e8dcf4f0f1fff9f2aaa5f2af">[email protected]</a> ~]# more /etc/passwd
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="20524f4f5460484c4d43454e16194e13">[email protected]</a> ~]# more /etc/shadow
root:*LOCK*:14600::::::
bin:*:17246:0:99999:7:::
daemon:*:17246:0:99999:7:::

4.查看机器最近成功登陆的事件和最后一次不成功的登陆事件,对应日志“/var/log/lastlog”,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="4e3c21213a0e2622232d2b207877207d">[email protected]</a> ~]# lastlog
Username     Port   From       Latest
root                    **Never logged in**
bin                    **Never logged in**
daemon                   **Never logged in**

5.查看机器当前登录的全部用户,对应日志文件“/var/run/utmp”,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="c3b1acacb783abafaea0a6adf5faadf0">[email protected]</a> ~]# who
stone  pts/0    2017-09-20 16:17 (X.X.X.X)
test01  pts/2    2017-09-20 16:47 (X.X.X.X)

6.查看机器创建以来登陆过的用户,对应日志文件“/var/log/wtmp”,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="ec9e838398ac8480818f8982dad582df">[email protected]</a> ~]# last
test01  pts/1    X.X.X.X  Wed Sep 20 16:50  still logged in 
test01  pts/2    X.X.X.X  Wed Sep 20 16:47 - 16:49 (00:02)  
stone  pts/1    X.X.X.X  Wed Sep 20 16:46 - 16:47 (00:01)  
stone  pts/0    X.X.X.X  Wed Sep 20 16:17  still logged in

7.查看机器所有用户的连接时间(小时),对应日志文件“/var/log/wtmp”,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="03716c6c77436b6f6e60666d353a6d30">[email protected]</a> ~]# ac -dp
     stone                11.98
Sep 15   total    11.98
     stone                67.06
Sep 18   total    67.06
     stone                1.27
     test01                0.24
Today    total    1.50

8.如果发现机器产生了异常流量,可以使用命令“tcpdump”抓取网络包查看流量情况或者使用工具”iperf”查看流量情况

9.可以查看/var/log/secure日志文件,尝试发现入侵者的信息,相关命令示例:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="82f0ededf6c2eaeeefe1e7ecb4bbecb1">[email protected]</a> ~]# cat /var/log/secure | grep -i "accepted password"
Sep 20 12:47:20 hlmcen69n3 sshd[37193]: Accepted password for stone from X.X.X.X port 15898 ssh2
Sep 20 16:17:47 hlmcen69n3 sshd[38206]: Accepted password for stone from X.X.X.X port 9140 ssh2
Sep 20 16:46:00 hlmcen69n3 sshd[38511]: Accepted password for stone from X.X.X.X port 2540 ssh2
Sep 20 16:47:16 hlmcen69n3 sshd[38605]: Accepted password for test01 from X.X.X.X port 10790 ssh2
Sep 20 16:50:04 hlmcen69n3 sshd[38652]: Accepted password for test01 from X.X.X.X port 28956 ssh2

10.查询异常进程所对应的执行脚本文件

a.top命令查看异常进程对应的PID

b.在虚拟文件系统目录查找该进程的可执行文件

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="285a47475c684044454b4d461e11461b">[email protected]</a> ~]# ll /proc/1850/ | grep -i exe
lrwxrwxrwx. 1 root root 0 Sep 15 12:31 exe -> /usr/bin/python
[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="1d6f7272695d7571707e78732b24732e">[email protected]</a> ~]# ll /usr/bin/python
-rwxr-xr-x. 2 root root 9032 Aug 18 2016 /usr/bin/python

11.如果确认机器已经被入侵,重要文件已经被删除,可以尝试找回被删除的文件

Note:

1>当进程打开了某个文件时,只要该进程保持打开该文件,即使将其删除,它依然存在于磁盘中。这意味着,进程并不知道文件已经被删除,它仍然可以向打开该文件时提供给它的文件描述符进行读取和写入。除了该进程之外,这个文件是不可见的,因为已经删除了其相应的目录索引节点。

2>在/proc 目录下,其中包含了反映内核和进程树的各种文件。/proc目录挂载的是在内存中所映射的一块区域,所以这些文件和目录并不存在于磁盘中,因此当我们对这些文件进行读取和写入时,实际上是在从内存中获取相关信息。大多数与 lsof 相关的信息都存储于以进程的 PID 命名的目录中,即 /proc/1234 中包含的是 PID 为 1234 的进程的信息。每个进程目录中存在着各种文件,它们可以使得应用程序简单地了解进程的内存空间、文件描述符列表、指向磁盘上的文件的符号链接和其他系统信息。lsof 程序使用该信息和其他关于内核内部状态的信息来产生其输出。所以lsof 可以显示进程的文件描述符和相关的文件名等信息。也就是我们通过访问进程的文件描述符可以找到该文件的相关信息。

3>当系统中的某个文件被意外地删除了,只要这个时候系统中还有进程正在访问该文件,那么我们就可以通过lsof从/proc目录下恢复该文件的内容。

假设入侵者将/var/log/secure文件删除掉了,尝试将/var/log/secure文件恢复的方法可以参考如下:

a.查看/var/log/secure文件,发现已经没有该文件

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="20524f4f5460484c4d43454e16194e13">[email protected]</a> ~]# ll /var/log/secure
ls: cannot access /var/log/secure: No such file or directory

b.使用lsof命令查看当前是否有进程打开/var/log/secure,

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="deacb1b1aa9eb6b2b3bdbbb0e8e7b0ed">[email protected]</a> ~]# lsof | grep /var/log/secure
rsyslogd  1264   root  4w   REG        8,1 3173904   263917 /var/log/secure (deleted)

c.从上面的信息可以看到 PID 1264(rsyslogd)打开文件的文件描述符为4。同时还可以看到/var/log/ secure已经标记为被删除了。因此我们可以在/proc/1264/fd/4(fd下的每个以数字命名的文件表示进程对应的文件描述符)中查看相应的信息,如下:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="9deff2f2e9ddf5f1f0fef8f3aba4f3ae">[email protected]</a> ~]# tail /proc/1264/fd/4
Sep 20 16:47:21 hlmcen69n3 sshd[38511]: pam_unix(sshd:session): session closed for user stone
Sep 20 16:47:21 hlmcen69n3 su: pam_unix(su-l:session): session closed for user root
Sep 20 16:49:30 hlmcen69n3 sshd[38605]: pam_unix(sshd:session): session closed for user test01
Sep 20 16:50:04 hlmcen69n3 sshd[38652]: reverse mapping checking getaddrinfo for 190.78.120.106.static.bjtelecom.net [106.120.78.190] failed - POSSIBLE BREAK-IN ATTEMPT!
Sep 20 16:50:04 hlmcen69n3 sshd[38652]: Accepted password for test01 from 106.120.78.190 port 28956 ssh2
Sep 20 16:50:05 hlmcen69n3 sshd[38652]: pam_unix(sshd:session): session opened for user test01 by (uid=0)
Sep 20 17:18:51 hlmcen69n3 unix_chkpwd[38793]: password check failed for user (root)
Sep 20 17:18:51 hlmcen69n3 sshd[38789]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=51.15.81.90 user=root
Sep 20 17:18:52 hlmcen69n3 sshd[38789]: Failed password for root from 51.15.81.90 port 47014 ssh2
Sep 20 17:18:52 hlmcen69n3 sshd[38790]: Connection closed by 51.15.81.90

d.从上面的信息可以看出,查看/proc/1264/fd/4就可以得到所要恢复的数据。如果可以通过文件描述符查看相应的数据,那么就可以使用I/O重定向将其重定向到文件中,如:

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="8bf9e4e4ffcbe3e7e6e8eee5bdb2e5b8">[email protected]</a> ~]# cat /proc/1264/fd/4 > /var/log/secure

e.再次查看/var/log/secure,发现该文件已经存在。对于许多应用程序,尤其是日志文件和数据库,这种恢复删除文件的方法非常有用。

[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="63110c0c17230b0f0e00060d555a0d50">[email protected]</a> ~]# ll /var/log/secure
-rw-r--r--. 1 root root 3173904 Sep 20 17:24 /var/log/secure
[<a href="/cdn-cgi/l/email-protection" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" data-cfemail="ec9e838398ac8480818f8982dad582df">[email protected]</a> ~]# head /var/log/secure
Sep 17 03:28:15 hlmcen69n3 sshd[13288]: reverse mapping checking getaddrinfo for 137-64-15-51.rev.cloud.scaleway.com [51.15.64.137] failed - POSSIBLE BREAK-IN ATTEMPT!
Sep 17 03:28:15 hlmcen69n3 unix_chkpwd[13290]: password check failed for user (root)
Sep 17 03:28:15 hlmcen69n3 sshd[13288]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=51.15.64.137 user=root
Sep 17 03:28:17 hlmcen69n3 sshd[13288]: Failed password for root from 51.15.64.137 port 59498 ssh2
Sep 17 03:28:18 hlmcen69n3 sshd[13289]: Received disconnect from 51.15.64.137: 11: Bye Bye
Sep 17 03:28:22 hlmcen69n3 sshd[13291]: reverse mapping checking getaddrinfo for 137-64-15-51.rev.cloud.scaleway.com [51.15.64.137] failed - POSSIBLE BREAK-IN ATTEMPT!
Sep 17 03:28:22 hlmcen69n3 unix_chkpwd[13293]: password check failed for user (root)
Sep 17 03:28:22 hlmcen69n3 sshd[13291]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=51.15.64.137 user=root
Sep 17 03:28:24 hlmcen69n3 sshd[13291]: Failed password for root from 51.15.64.137 port 37722 ssh2
Sep 17 03:28:25 hlmcen69n3 sshd[13292]: Received disconnect from 51.15.64.137: 11: Bye Bye

总结

以上所述是小编给大家介绍的Linux服务器被黑以后的详细处理步骤,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对网站的支持!

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稳了!魔兽国服回归的3条重磅消息!官宣时间再确认!

昨天有一位朋友在大神群里分享,自己亚服账号被封号之后居然弹出了国服的封号信息对话框。

这里面让他访问的是一个国服的战网网址,com.cn和后面的zh都非常明白地表明这就是国服战网。

而他在复制这个网址并且进行登录之后,确实是网易的网址,也就是我们熟悉的停服之后国服发布的暴雪游戏产品运营到期开放退款的说明。这是一件比较奇怪的事情,因为以前都没有出现这样的情况,现在突然提示跳转到国服战网的网址,是不是说明了简体中文客户端已经开始进行更新了呢?