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Linux RedHat dump security hole


From: davem+ () andrew cmu edu (David J Meltzer)
Date: Tue, 23 Jan 1996 11:16:00 -0500


   There is a security hole in RedHat 2.1, which installs /sbin/dump suid
root.  The dump program makes no provisions for checking file permissions,
allowing any user on the system to read arbitrary files on the system.
Dump checks permissions only on the directory you specify to backup, and
not on files or subdirectories.
The process to exploit this is to backup the files via dump as if it was
a normal backup to a temporary file, and then restore the temporary file
with /sbin/restore to your own directory.  The solution is simple, don't
run dump suid root on your system.

                   Program: /sbin/dump incorrectly installed
Affected Operating Systems: RedHat 2.1 linux distribution
              Requirements: account on system
                     Patch: chmod -s /sbin/dump
       Security Compromise: read arbitrary files on system
                    Author: Dave M. (davem () cmu edu)
                  Synopsis: dump fails to check file permissions against
                            user running dump, or to give up suid when
                            backing up a filesystem.

Exploit:
$ /sbin/dump 0uf woot.dump DIRECTORY_FILE_TO_READ_IS_IN




       /-------------\
       |David Meltzer|
       |davem () cmu edu|
 /--------------------------\
 |School of Computer Science|
 |Carnegie Mellon University|
 \--------------------------/



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