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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Hi, <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">I have found a weird behavior in auditd.
</span><span lang="EN-IN" style="font-family:"Arial",sans-serif">File “/abc” does not exist.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><u><span style="font-family:"Arial",sans-serif">audit.rules:<o:p></o:p></span></u></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-IN" style="font-size:11.0pt;font-family:"Arial",sans-serif;color:black">-a always,exit -F arch=b32 -S open -S openat<o:p></o:p></span></p>
<p style="margin:0cm;margin-bottom:.0001pt"><span lang="EN-IN" style="font-size:11.0pt;font-family:"Arial",sans-serif;color:black">-a always,exit -F arch=b64 -S open -S openat<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">A non-root user executes “echo > /abc”, it doesn’t get logged in audit.log. Same with “echo > /etc/abc”<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">A non-root user executes “cat /abc”, it gets logged in audit.log<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">Since auditd is monitoring all the open and openat syscalls, ideally both the cases (i.e. read and write) should have be logged.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">After I execute “chmod a+w /” then “chmod a-w /”,
</span><span lang="EN-IN" style="font-family:"Arial",sans-serif">if a non-root user executes “echo > /abc”, then it gets logged in audit.log.</span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">This looks like a bug to me. Kindly let me know if it’s a bug or an intended feature.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">System used to test:
</span><span style="font-family:"Arial",sans-serif">Linux 5.4.0-56-generic #62-Ubuntu SMP x86_64 x86_64 x86_64 GNU/Linux<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-IN" style="font-family:"Arial",sans-serif">Regards,<o:p></o:p></span></p>
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<p class="MsoNormal" style="line-height:11.25pt"><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#000001">Shourya Jaiswal</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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