Reddit 上的这篇文章让我查看了我的日志。就在那时，我发现了以下条目，它们出现在两天内。“用户”是我的用户帐户。
Aug 4 22:50:37 UbuntuSystem sudo: pam_unix(sudo:session): session opened for user root by user(uid=1000)
Aug 4 22:50:39 UbuntuSystem sudo: pam_unix(sudo:session): session closed for user root
Aug 4 22:51:16 UbuntuSystem su[10710]: Successful su for user by root
Aug 4 22:51:16 UbuntuSystem su[10710]: + ??? root:user
Aug 4 22:51:16 UbuntuSystem su[10710]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10710]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10720]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10720]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10720]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10720]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10735]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10735]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10735]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10735]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10763]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10763]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10763]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10763]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10773]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10773]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10773]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10773]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10788]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10788]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10788]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10788]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10801]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10801]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10801]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10801]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10814]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10814]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10814]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10814]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10829]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10829]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10829]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10829]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10842]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10842]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10842]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10842]: pam_unix(su:session): session closed for user user
Aug 4 22:51:17 UbuntuSystem su[10855]: Successful su for user by root
Aug 4 22:51:17 UbuntuSystem su[10855]: + ??? root:user
Aug 4 22:51:17 UbuntuSystem su[10855]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 22:51:17 UbuntuSystem su[10855]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11153]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11153]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11153]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11153]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11166]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11166]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11166]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11166]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11181]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11181]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11181]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11181]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11193]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11193]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11193]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11193]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11211]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11211]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11211]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11211]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11226]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11226]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11226]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11226]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11241]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11241]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11241]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11241]: pam_unix(su:session): session closed for user user
Aug 4 23:41:39 UbuntuSystem su[11253]: Successful su for user by root
Aug 4 23:41:39 UbuntuSystem su[11253]: + ??? root:user
Aug 4 23:41:39 UbuntuSystem su[11253]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 4 23:41:39 UbuntuSystem su[11253]: pam_unix(su:session): session closed for user user
Aug 4 23:42:18 UbuntuSystem gnome-screensaver-dialog: gkr-pam: unlocked login keyring
Aug 4 23:42:33 UbuntuSystem polkitd(authority=local): Unregistered Authentication Agent for unix-session:/org/freedesktop/ConsoleKit/Session2 (system bus name :1.48, object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)
Aug 15 20:17:01 UbuntuSystem CRON[26579]: pam_unix(cron:session): session opened for user root by (uid=0)
Aug 15 20:17:01 UbuntuSystem CRON[26579]: pam_unix(cron:session): session closed for user root
Aug 15 21:15:15 UbuntuSystem su[27098]: Successful su for user by root
Aug 15 21:15:15 UbuntuSystem su[27098]: + ??? root:user
Aug 15 21:15:15 UbuntuSystem su[27098]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 15 21:15:15 UbuntuSystem su[27098]: pam_unix(su:session): session closed for user user
Aug 15 21:17:01 UbuntuSystem CRON[27141]: pam_unix(cron:session): session opened for user root by (uid=0)
Aug 15 21:17:01 UbuntuSystem CRON[27141]: pam_unix(cron:session): session closed for user root
除了这些迭代之外，我发现类似的输出的唯一其他时间是在尝试访客帐户时：
Aug 11 22:38:49 UbuntuSystem lightdm: pam_unix(lightdm:session): session closed for user lightdm
Aug 11 22:38:49 UbuntuSystem groupadd[2918]: group added to /etc/group: name=guest-4Eflre, GID=125
Aug 11 22:38:49 UbuntuSystem groupadd[2918]: group added to /etc/gshadow: name=guest-4Eflre
Aug 11 22:38:49 UbuntuSystem groupadd[2918]: new group: name=guest-4Eflre, GID=125
Aug 11 22:38:50 UbuntuSystem useradd[2922]: new user: name=guest-4Eflre, UID=115, GID=125, home=/, shell=/bin/bash
Aug 11 22:38:50 UbuntuSystem usermod[2927]: change user 'guest-4Eflre' password
Aug 11 22:38:50 UbuntuSystem chage[2932]: changed password expiry for guest-4Eflre
Aug 11 22:38:50 UbuntuSystem chfn[2935]: changed user 'guest-4Eflre' information
Aug 11 22:38:50 UbuntuSystem usermod[2943]: change user 'guest-4Eflre' home from '/' to '/tmp/guest-4Eflre'
Aug 11 22:38:50 UbuntuSystem su[2948]: Successful su for guest-4Eflre by root
Aug 11 22:38:50 UbuntuSystem su[2948]: + ??? root:guest-4Eflre
Aug 11 22:38:50 UbuntuSystem su[2948]: pam_unix(su:session): session opened for user guest-4Eflre by (uid=0)
Aug 11 22:38:50 UbuntuSystem su[2948]: pam_unix(su:session): session closed for user guest-4Eflre
Aug 11 22:38:50 UbuntuSystem lightdm: pam_unix(lightdm-autologin:session): session opened for user guest-4Eflre by (uid=0)
Aug 11 22:38:50 UbuntuSystem lightdm: pam_ck_connector(lightdm-autologin:session): nox11 mode, ignoring PAM_TTY :0
我可能必须补充一点，我只是最近（ 8 月 4 日）才建立我的系统。
这种行为正常吗？所有 su 命令到底是怎么回事？我是否需要担心我的系统可能受到威胁？
提前谢谢了。
答案1
当您从 root 切换到用户时会出现这些警告。
看来你没有什么问题。
答案2
这些都是不是从你跑步的时候开始sudo。但它们也不是问题。
消息称：
Successful su for user by root无论何时登录都会发生这种情况。无论您是以真实用户还是访客用户身份登录，登录屏幕运行为root，因此必须改变用户身份从 root 到非root用户作为登录过程的一部分。
这不是user成为root。这就是root成为user。
答案3
我想我可能已经找到至少一个罪魁祸首：
Aug 21 16:15:09 UbuntuSystem su[30135]: Successful su for user by root
Aug 21 16:15:09 UbuntuSystem su[30135]: + ??? root:user
Aug 21 16:15:09 UbuntuSystem su[30135]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 21 16:15:09 UbuntuSystem su[30135]: pam_unix(su:session): session closed for user user
Aug 21 16:15:09 UbuntuSystem sudo: pam_unix(sudo:session): session closed for user root
Aug 21 16:15:12 UbuntuSystem sudo: user : TTY=unknown ; PWD=/home/user ; USER=root ; COMMAND=/usr/lib/jupiter/scripts/cpu-control high
Aug 21 16:15:12 UbuntuSystem sudo: pam_unix(sudo:session): session opened for user root by (uid=1000)
Aug 21 16:15:12 UbuntuSystem su[30174]: Successful su for user by root
Aug 21 16:15:12 UbuntuSystem su[30174]: + ??? root:user
Aug 21 16:15:12 UbuntuSystem su[30174]: pam_unix(su:session): session opened for user user by (uid=0)
Aug 21 16:15:12 UbuntuSystem su[30174]: pam_unix(su:session): session closed for user user
Aug 21 16:15:12 UbuntuSystem sudo: pam_unix(sudo:session): session closed for user root
在这种情况下，条目与 Jupiter 电源小程序有关，并且在更改 CPU 电源模式时会特别出现。由于在任何其他情况下都没有提到 Jupiter，因此我无法确定它们是否可以归因于同一进程。
我将继续监控我的日志并在此发布任何进一步的结果。