Here are text-based graphical illustrations and structured layouts designed to be integrated directly into your type_confusion.md file to maximize readability and clarify the memory alignment.
📊 Visualizing the Memory Overlap (Phase 2 & Root Cause)
When the application allocates a SafeWidget, memory is laid out sequentially. However, because handle() casts this memory space directly to a PrivWidget*, the CPU reinterprets those same exact bytes.
The diagram below illustrates how SafeWidget::name maps perfectly to the pointers in PrivWidget:
SAFEWIDGET AS ALLOCATED PRIVWIDGET AS INTERPRETED
+---------------------------+ +---------------------------+
Bytes 00-07 | vptr (8 bytes) | ====> | vptr (8 bytes) |
+---------------------------+ +---------------------------+
Bytes 08-11 | kind = 1 (int) | ====> | kind = 1 (int) |
+---------------------------+ +---------------------------+
Bytes 12-15 | pad = 0 (int) | ====> | pad = 0 (int) |
+---------------------------+ +---------------------------+
Bytes 16-23 | [0] | | |
| [1] Attacker Injection | | secret_ptr |
| ... (&g_secret) | ====> | (Points to Flag!) |
| [7] | | |
+---------------------------+ +---------------------------+
Bytes 24-31 | [8] | | |
| [9] Attacker Injection | | callback |
| ... (&win) | ====> | (Points to win()) |
| [15] | | |
+---------------------------+ +---------------------------+
Bytes 32-47 | [16]...[31] Remaining Buffer| | (Out of bounds |
+---------------------------+ | for PrivWidget) |
+---------------------------+
🔄 The Confused Cast Trigger Flow (Phase 3)
The pipeline below tracks how execution shifts step-by-step from data ingestion to arbitrary read and code redirection during the SHOW 0 command execution:
[ STEP 1: INGESTION ]
Attacker sends ADD SAFE HEX command with crafted payload
|
v
[ STEP 2: ALLOCATION ]
Heap object created as SafeWidget (kind=1)
name[0..7] = 0x5cdf40a98008 (&g_secret)
name[8..15] = 0x5cdf40a962f9 (&win)
|
v
[ STEP 3: THE CONFUSED CAST ]
static_cast<PrivWidget*>(w) forces the compiler to trust the type
|
+-----------------------------+
| |
v v
[ PRIMITIVE A: ARBITRARY READ ] [ PRIMITIVE B: CONTROL HIJACK ]
Dereferences p->secret_ptr Executes p->callback()
| |
v v
Reads address 0x5cdf40a98008 Jumps execution to 0x5cdf40a962f9
| |
v v
Prints: "FLAG{type_...}" Enters win() -> Code executed!
🔍 Offset Alignment Quick-Reference
This table maps the exact runtime values captured in your exploit log against the variables they impersonate:
| Offset (Bytes) | Field Source (SafeWidget) |
Reinterpreted Target (PrivWidget) |
Injected Exploitation Value | Resolution Effect |
|---|---|---|---|---|
+00 to +07 |
vptr |
vptr |
Valid Virtual Table | Normal object handling |
+08 to +11 |
kind (1) |
kind |
0x00000001 |
Fails logical checking if validated |
+16 to +23 |
name[0..7] |
secret_ptr |
0x5cdf40a98008 |
Leaks flag memory contents |
+24 to +31 |
name[8..15] |
callback |
0x5cdf40a962f9 |
Forces jump to win() function |