need help interpreting ausearch results

[Burn Alting]

Stefano,

I assume your rules are file watches. Yes, on the surface, it looks like
a service user, lanogbar, is running a php application which has make
the chmod  system call making the change to 777 (ie a1=1ff in the second
event shown).

You could check the process id's (the one which does the chmod - pid =
8804, or the parent process id - ppid = 27717) although these might be
temporary processes ... perhaps you could turn on execution audit

-a exit,always -F arch=b32 -S execve -k cmds
-a exit,always -F arch=b64 -S execve -k cmds


perhaps also specific chmods also ...

-a always,exit -F arch=b32 -S chmod -S fchmod -S fchmodat -S chown -S
fchown -S fchownat -S lchown -S setxattr -S lsetxattr -S fsetxattr -S
removexattr -S lremovexattr -S fremovexattr -F auid!=0 -F auid!
=4294967295 -k perm_mod
-a always,exit -F arch=b64 -S chmod -S fchmod -S fchmodat -S chown -S
fchown -S fchownat -S lchown -S setxattr -S lsetxattr -S fsetxattr -S
removexattr -S lremovexattr -S fremovexattr -F auid!=0 -F auid!
=4294967295 -k perm_mod

Also, as Peter suggests it does help if you present the output from
ausearch -i rather than the raw data from /var/log/audit/audit.log.




On Sun, 2013-12-22 at 09:05 -0800, Peter Moody wrote:
> What's the actual rule? On my system, syscall 88 is either symlink (64 bit) or reboot (32 bit).
> 
> On Sat, Dec 21 2013 at 04:48, Stefano Schiavi wrote:
> > Hello,
> >
> > Could anyone help with this? I really don't know where else to ask.
> >
> > Thank you very much.
> > Stefano
> >
> >
> > On 12/15/13, 12:19 AM, Stefano Schiavi wrote:
> >> Hello,
> >>
> >> Thank you Steve and all for keeping up the great work here.
> >>
> >> Some time ago I setup some audit rules to monitor what would change the permissions of the
> >> public_html directory since we found that once in a while it would change to 777 out of the
> >> blue.
> >>
> >> It happened again yesterday and I believe these parts of the log represent when the issue
> >> happened:
> >>
> >> type=PATH msg=audit(1386933561.795:7958476): item=2 name="./www" inode=4980752 dev=08:08
> >> mode=0120777 ouid=501 ogid=501 rdev=00:00
> >> type=PATH msg=audit(1386933561.795:7958476): item=1 name="./" inode=4980737 dev=08:08
> >> mode=040711 ouid=501 ogid=501 rdev=00:00
> >> type=PATH msg=audit(1386933561.795:7958476): item=0 name="public_html"
> >> type=CWD msg=audit(1386933561.795:7958476):  cwd="/home/lanogbar"
> >> type=SYSCALL msg=audit(1386933561.795:7958476): arch=c000003e syscall=88 success=yes exit=0
> >> a0=1306d160 a1=1306d200 a2=11 a3=0 items=3 ppid=18728 pid=18731 auid=0 uid=501 gid=501
> >> euid=501 suid=501 fsuid=501 egid=501 sgid=501 fsgid=501 tty=(none) ses=117304 comm="gtar"
> >> exe="/bin/tar" key="lanogbar-www"
> >>
> >>
> >> This is just a guess though and I can not be sure as I have no experience parsing the
> >> logs. Looking through with the I flag we can see the following::
> >>
> >> type=PATH msg=audit(12/13/2013 15:00:03.759:7970202) : item=0
> >> name=/home/lanogbar/public_html/ inode=4980744 dev=08:08 mode=dir,750 ouid=lanogbar
> >> ogid=nobody rdev=00:00
> >> type=CWD msg=audit(12/13/2013 15:00:03.759:7970202) : cwd=/home/lanogbar/public_html
> >> type=SYSCALL msg=audit(12/13/2013 15:00:03.759:7970202) : arch=x86_64 syscall=chmod
> >> success=yes exit=0 a0=1585e520 a1=1ff a2=2f a3=146c1d40 items=1 ppid=27717 pid=8804 auid=root
> >> uid=lanogbar gid=lanogbar euid=lanogbar suid=lanogbar fsuid=lanogbar egid=lanogbar
> >> sgid=lanogbar fsgid=lanogbar tty=(none) ses=117304 comm=php exe=/usr/bin/php
> >> key=lanogbar-public_html
> >>
> >> Do you think this is relevant?
> >> If so it would seem a php script was responsible.
> >>
> >> Would you have any suggestion on how to identify the script?
> >>
> >> Thank you very much for the very valuable help.
> >> Kind regards,
> >> Stefano
> >
> > --
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> 
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