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Date:      Tue, 24 Jul 2001 13:47:58 -0400 (EDT)
From:      Rob Simmons <rsimmons@wlcg.com>
To:        Jon Loeliger <jdl@jdl.com>
Cc:        <security@FreeBSD.ORG>
Subject:   Re: Security Check Diffs Question
Message-ID:  <20010724134421.I44940-100000@mail.wlcg.com>
In-Reply-To: <200107241632.LAA05639@chrome.jdl.com>

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If you have access to the same binaries on another machine, run ident
against both.  If there are _no_ RCS keyword strings in the questionable
binaries, there is definitely a problem.

Robert Simmons
Systems Administrator
http://www.wlcg.com/

On Tue, 24 Jul 2001, Jon Loeliger wrote:

> Hi Folks,
>
> This morning, on a machine that's been up for 33 days,
> I suddenly saw these /etc/security diffs:
>
> <host> setuid diffs:
> 20,22c20,22
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chfn
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chpass
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chsh
> ---
> > 8047 -r-sr-xr-x  5 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chfn
> > 8047 -r-sr-xr-x  5 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chpass
> > 8047 -r-sr-xr-x  5 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/chsh
> 53,55c53,55
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchfn
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchpass
> < 8047 -r-sr-xr-x  6 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchsh
> ---
> > 8270 -r-sr-xr-x  1 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchfn
> > 8047 -r-sr-xr-x  5 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchpass
> > 8047 -r-sr-xr-x  5 root  wheel  32184 Nov 20 06:01:52 2000 /usr/bin/ypchsh
>
>
> So, how paranoid am I here?  How concerned am I?
> What compromised of my system just took place?
> Couple things to notice:
>
>     - The files now take fewer 512K blocks,
>       but their sizes are the same?
>
>     - Most of the inodes staid the same.  Exact same.
>       Are these hard linked files? Should be, right?
>
>     - The inode for ypchfn changed!
>       It's no longer hard linked, right?
>
> No form of disk restructuring, fsck, defrag, etc, was initiated by me.
>
> Note that:
>
>     www 181 # cmp /usr/bin/{ypchpass,ypchfn}
>     /usr/bin/ypchpass /usr/bin/ypchfn differ: char 25, line 1
>
> Here is a `strings /usr/bin/ypchfn`:
>
>     www 182 # strings /usr/bin/ypchfn
>     /usr/libexec/ld-elf.so.1
>     FreeBSD
>     libcrypt.so.2
>     _DYNAMIC
>     _init
>     __deregister_frame_info
>     crypt
>     strcmp
>     _fini
>     _GLOBAL_OFFSET_TABLE_
>     __register_frame_info
>     libc.so.4
>     strerror
>     execl
>     environ
>     fprintf
>     __progname
>     __error
>     setgid
>     __sF
>     execv
>     getpwuid
>     getpwnam
>     atexit
>     exit
>     strchr
>     execvp
>     setuid
>     _etext
>     _edata
>     __bss_start
>     _end
>     8/u
>     QR2cc.wsLFbKU
>     root
>
> If someone didn't hack my system, I took a disk hit and lost
> part of that file, right?
>
> What other log files am I disecting or where else am I poking
> for further evidence?
>
> Am I blowing away the bogus(?) /usr/bin/ypchfn and re-making
> it a hard link to the others again?
>
> jdl
>
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>
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