COMMAND
Pine
SYSTEMS AFFECTED
Linux (others?)
PROBLEM
Jesse Brown discovered what appears to be a rather serious bug in
the Pine Mail Client, that allows a user of Pine to overwrite ANY
file, with ANY permissions or ownerships in their home directory
(including sub-directorys).
This bug can be used to overwrite a protected login script, or to
overwrite a resource file (like .pinerc). This can be of serious
concern to those that use Pine as a shell for users, as this can
allow them to modify or create files that could be used to gain
shell access. (Such as .rhosts, .forward, etc.)
All that is required to exploit this apparent bug is to open up a
message attachment using the Pine attachment viewer, and save the
attachment. If you want to overwrite ANY file anywhere in the
users home directory, just enter the file name and select
overwrite. This does not work outside of the users home directory
BTW.
The interesting thing about this is that it appears to completly
bypass any filesystem level security (permissions, owner, etc.).
Also, when pine overwrites the file it sets the mode to 622
(-rw-r--r--) and the owner to the current user (the pine
executable IS NOT setuid root). This has been tested with Pine
version 3.95 & 3.96 on Linux systems.
SOLUTION
Nothing yet.