ShmooCon 20062006-01-06

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It took a few days of (interspersed) debugging but I finally got memory breakpoints implemented in the Python Win32 debugging engine I wrote last weekend. It's built on the Python ctypes module, which I'm very fond of. Many thanks to the people I leaned on at various times while pulling my hair out trying to figure out what was wrong (hoglund, spoon, skape, drew ...). I'll make it available at some point, it's currently way too ugly but very functional:

    def attach:
    def bp_del:
    def bp_del_mem:
    def bp_is_ours:
    def bp_is_ours_mem:
    def bp_set:
    def bp_set_mem:
    def cleanup:
    def debug_event_loop:
    def detach:
    def disasm:
    def dump_context:
    def enumerate_threads:
    def exception_handler_breakpoint:
    def exception_handler_guard_page:
    def exception_handler_single_step:
    def func_resolve:
    def get_thread_context:
    def hex_dump:
    def hide_debugger:
    def is_address_on_stack:
    def is_printable_ascii:
    def is_printable_unicode:
    def little_endian:
    def load:
    def process_restore:
    def process_snapshot:
    def read_process_memory:
    def resume_thread:
    def set_callback:
    def set_register:
    def set_thread_context:
    def single_step:
    def smart_dereference:
    def stack_range:
    def suspend_thread:
    def terminate_process:
    def virtual_protect:
    def virtual_query:
    def write_process_memory:
    
It's interesting being able to quickly prototype various debugging based ideas in Python:
    pydbg = pydbg()
    
    pydbg.set_callback(EXCEPTION_BREAKPOINT,       h_bp)
    pydbg.set_callback(EXCEPTION_ACCESS_VIOLATION, h_av)
    
    try:
        pydbg.attach(pid)
    
        recv     = pydbg.func_resolve("ws2_32",  "recv")
        recvfrom = pydbg.func_resolve("ws2_32",  "recvfrom")
    
        pydbg.bp_set(recv)
        pydbg.bp_set(recvfrom)
    
        pydbg.debug_event_loop()
    except pdx, x:
        sys.stderr.write(x.__str__() + "\n")
There is still an oustanding question of how exactly Windows deals with guard pages. I put that question up in the forums so people can respond to it:

http://www.openrce.org/forums/posts/110

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Debugger Debugging Madness2005-11-02

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Recently, I was setting up a new installation of IDA and decided to document all of my customizations for ease of portability. I am curious to hear about what other customizations people use / have come across. Should make for an interesting dialog. Here are the customizations I use:

---------- ida.idc ----------
#include 
#include 
#include 
#include 

static main(void) {

//
// This function is executed when IDA is started.
//
// Add statements to fine-tune your IDA here.
//

    AddHotkey("Ctrl-Shift-X",     "export_disassembly");
    AddHotkey("Ctrl-Shift-J",     "jump_to_func_top");
    AddHotkey("Ctrl-Shift-Enter", "track_follow");
    AddHotkey("Ctrl-Shift-N",     "track_name");
...

---------- ida.cfg ----------
Some of these customizations were gleaned from Nicolas Brulez

// This prefix is used when a new
// name is generated
// changed this from 'a' to 'str->'
ASCII_PREFIX = "str->"

// Maximal length of new names
// (you may specify values up to 511)
// increased this to 128
MAX_NAMES_LENGTH = 128

// asm specific character, added '-' and '>'
NameChars = "$?@->"

SHOW_XREFS        = 4
SHOW_BASIC_BLOCKS = YES
SHOW_SP           = YES

---------- idagui.cfg ----------
HELPFILE = "c:\\OPCODES.HLP"

// Display the Edit,Patch submenu
DISPLAY_PATCH_SUBMENU = YES

// Display the expressions/IDC command line
DISPLAY_COMMAND_LINE  = YES

// display referenced items
"ChartXrefsTo"   = "Ctrl-Shift-T"

// display referencing items
"ChartXrefsFrom" = "Ctrl-Shift-F"

// lock the current highlighted text
"LockHighlight"  = "Ctrl-H"

All of the above referenced files are available from my file respository on OpenRCE.

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IDA Disassembly and Graph Coloring2005-09-20

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ToorCon was awesome. This was my first time out to that con (as well as San Diego for that matter) and it more then lived up to expectations. The venue was good, the weather was great and the party was successful, thanks in no small part due to a financial contribution from Microsoft I'm sure.

There were a number of good talks there. Among the more unique/interesting was Skape's presentation on "temporal return addresses" and Christopher Abad's talk where he cracked basic crypto with Photoshop and demo-ed a multi-color ASCII "video" streamer he wrote. Some of Christopher's work can be found at http://the-mathclub.net.

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