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0.85

    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.