|Summary||Groupware message receive integer overflow|
|Discovered By||Sean (infamous42md)|
|Fixed In Release||0.82|
Integer overflow in memory allocation results in heap overflow. By passing the
size variable as
~0, integer overflows to 0 when 1 is added in
malloc(0) call results in 16 bytes of memory being allocated on IA- 32.
Then we can overflow the heap when
nm_read_all() is called next step.
Usually cases like this suck for exploitation, because the len (
~0) is so
large that a following call to
strcpy() will just run into
kernel mem or unmapped address and fault. However in this case we read the
data from the network via a
read() call, so we can just stop sending data and
close the connection to short out before
~0 bytes are read. However, this is
triggered by input from the server, not directly from a client. Someone
running a malicious groupware server could leverage this to run arbitrary code
on the client.
Bounds checking was added.