clarified the vulnerability with bzgrep

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@6705 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/bzip2.xml

@@ -36,8 +36,10 @@ GCC, Glibc, and Make</seg></seglistitem>
 
 <screen><userinput>patch -Np1 -i ../&bzip2-docs-patch;</userinput></screen>
 
-<para><command>Bzgrep</command> fails to sufficiently sanitise filenames passed
-to it. Apply the following to address this:</para>
+<para><command>Bzgrep</command> does not escape '|' and '&amp;' in filenames passed
+to it. This allows arbitrary commands to be executed with the privileges of the
+user running <command>bzgrep</command>. Apply the following to address this:
+</para>
 
 <screen><userinput>patch -Np1 -i ../&bzip2-bzgrep-patch;</userinput></screen>