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Annotation of embedaddon/mtr/SECURITY, revision 1.1.1.1

1.1       misho       1: SECURITY ISSUES RELATED TO MTR
                      2: 
                      3: You can limit mtr usage to the root user by not putting a setuid bit
                      4: on the mtr binary. In that case, the security implications are
                      5: minimal. 
                      6: 
                      7: Or you can make mtr setuid-root, and the following applies to you....
                      8: 
                      9: Since mtr is installed as suid-root, some concern over security is
                     10: justified.  Since version 0.21 of mtr, does the following two things
                     11: after it is launched:
                     12: 
                     13: *  mtr requests a pair of raw sockets from the kernel.  
                     14: *  mtr sets the effective uid to match the real uid.
                     15: 
                     16: See main() in mtr.c and net_preopen() in net.c for the details of this
                     17: process.  Note that no code from GTK+ or curses is executed before the
                     18: drop in permissions.
                     19: 
                     20: This should severely limit the possibilities of using mtr to breach
                     21: system security.  This means the worst case scenerio is as follows:
                     22: 
                     23: Due to some oversight in the mtr code, a malicious user is able to
                     24: overrun one of mtr's internal buffers with binary code that is
                     25: eventually executed.  The malicious user is still not able to read
                     26: from or write to any system files which they wouldn't normally have
                     27: permission to write to.  The only priveledge gained is access to the
                     28: raw socket descriptors, which would allow the malicious user to listen
                     29: to all ICMP packets arriving at the system, and send forged packets
                     30: with arbitrary contents.
                     31: 
                     32: The mtr-code does its best to prevent calling of external library
                     33: code before dropping privileges. It seems that C++ library code has 
                     34: the ability to issue a "please execute me before calling main" to the
                     35: loader/linker.  That would mean that we're still vulnerable to 
                     36: errors in that code. This is why I would prefer to drop the backends, 
                     37: have mtr-core always run in "raw" mode, and have the backends interpret
                     38: the output from the mtr-core. Maybe a nice project for a college-level
                     39: student. 
                     40: 
                     41: If you have further questions or comments about security issues,
                     42: please direct them to the mtr mailing list.  See README for details.