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Examples / Report #2823554 Saved analysis

Buffer overflow in strcpy

curl · 2024-11-0628.3s analysis · $0.013 in model calls

What the report claims

The report claims a buffer overflow in curl's use of strcpy leads to arbitrary code execution.

Compare with curl's recorded outcome

Labeled AI slop

curl's maintainer lists this report as AI slop

Shown for comparison after analysis. The pipeline did not see this label.

ProveIt's finding

Code contradicts the claim

The code provides evidence against the report's central claim. Review the cited lines before deciding.

curl policy: Local attackers already present
Why this finding?
  • The report's own stack trace shows the strcpy call occurs in OpenSSL (libcrypto.so.3), not in curl. Functions CRYPTO_strdup and CONF_modules_load_file_ex are OpenSSL internals.
  • The provided curl source (src/tool_main.c) contains no strcpy usage, and no other curl source is provided that would show a vulnerable strcpy.
  • The POC is a standalone local exploit that calls execve("/bin/sh") directly; it does not interact with curl or demonstrate a curl input path to the alleged overflow.
  • Per project policy, issues only exploitable by a local attacker already present on the system are not considered curl security problems.
What still needs checking
  • A concrete curl command line, configuration, or API sequence that triggers the OpenSSL module loading path.
  • Evidence that the OpenSSL strcpy is reachable via documented curl usage (not API misuse).
  • A reproduction that actually invokes curl and causes the overflow, rather than a standalone execve call.
How this analysis ran 6 claims · 2 citations verified

Checked against curl master on 2024-11-06 (380790b2449e). Dev evaluation split. Citation verification checks that a referenced line was in the evidence; it does not prove the model interpreted it correctly.

1 · Grounding
partially grounded
no model · 2 references checked out, 1 did not
2 · Claims
NVIDIA-Nemotron-3-Nano-30B-A3B
6 claims · 3789 tokens · $0.0003
3 · Evidence
1 code snippets
real curl source at 380790b2449e
4 · Judgment
Nemotron-3-Ultra-550b-a55b
8479 tokens · 14.2s · $0.0129
5 · Receipts
2 of 6 citations verified
every citation must point at code the judge was shown
Review a draft reply to the reporter

Edit and verify before sending.

The stack trace you provided shows the strcpy call inside OpenSSL (CRYPTO_strdup, CONF_modules_load_file_ex in libcrypto.so.3), not in curl. The curl source at the revision you target contains no strcpy in the provided main path. Your POC simply calls execve("/bin/sh") directly and does not demonstrate a curl vulnerability. To pursue this, please provide: (1) a curl command line or API sequence that reaches the OpenSSL code, (2) evidence the OpenSSL path is triggered by documented curl usage, and (3) a reproduction that actually runs curl. Without these, the issue appears to be in OpenSSL, not curl, and requires local access per our policy.

Inspect all claims and source code 6 claims · 1 code excerpts

Report claims

C1flaw contradicted

The use of strcpy() in curl lacks bounds checking and can overflow the destination buffer.

Read the reasoning

The report's own stack trace places the strcpy call inside OpenSSL (CRYPTO_strdup, CONF_modules_load_file_ex), not curl. The provided curl source snippet contains no strcpy calls. The claim that curl uses strcpy unsafely is not supported by the evidence.

src/tool_main.c:227
C2location contradicted

The overflow occurs in the curl program, not in OpenSSL, during the strcpy call.

Read the reasoning

The stack trace explicitly shows the call chain passing through OpenSSL library functions (CRYPTO_strdup, CONF_modules_load_file_ex). The overflow occurs in OpenSSL's strcpy usage, not curl's.

report:0
C3trigger not verifiable

An attacker can provide an input string larger than the allocated buffer to strcpy.

Read the reasoning

The report does not identify which curl input (command-line option, config, URL, etc.) triggers the OpenSSL code path. No attacker-controlled input path in curl is demonstrated.

src/tool_main.c:227
C4impact not verifiable

Overwriting the return address allows execution of arbitrary code, leading to remote code execution.

Read the reasoning

The exploit demonstration is a local standalone binary exploit, not a curl vulnerability exploit. No remote code execution via curl is shown.

report:0
C5reproduction contradicted

The exploit uses a crafted payload that fills the buffer, overwrites the return address with a gadget, and calls system("/bin/sh").

Read the reasoning

The POC does not reproduce a curl vulnerability. It simply spawns a shell directly via execve, proving nothing about curl.

report:0
C6impact not verifiable

The vulnerability can result in command shell, system takeover, and other security compromises.

Read the reasoning

No curl-specific attack vector is established, so impact claims are unverifiable.

report:0

Deterministic checks that failed

  • symbol rip exists in other curl releases but not at 380790b2449e
Read the original report (excerpt)

Full report on HackerOne ↗

**Buffer Overflow Exploit Analysis** The vulnerability in the program is a classic case of a buffer overflow, triggered by the unsafe use of the `strcpy()` function, which lacks bounds checking. The following section describes the vulnerability, how the return address is overflowed, and how the exploit works to achieve remote code execution. **Vulnerable Function:** The vulnerability occurs due to the use of `strcpy()` in the program, which copies data from a source buffer to a destination buffer without verifying that the destination buffer is large enough to hold the incoming data. If the input string is larger than the allocated buffer size, it results in a buffer overflow, which can lead to arbitrary memory overwrites. **Stack Trace and Buffer Overflow Location:** The overflow happens when the `strcpy()` function is called. Here's the relevant stack trace from GDB, showing the function call sequence: ``` #0 __strcpy_evex () at ../sysdeps/x86_64/multiarch/strcpy-evex.S:94 #1 0x00007ffff765d2cd in CRYPTO_strdup () from /lib/x86_64-linux-gnu/libcrypto.so.3 #2 0x00007ffff756ef96 in ?? () from /lib/x86_64-linux-gnu/libcrypto.so.3 #3 0x00007ffff7570103 in ?? () from /lib/x86_64-linux-gnu/libcrypto.so.3 #4 0x00007ffff7571ef9 in CONF_modules_load_file_ex () from /lib/x86_64-linux-gnu/libcrypto.so.3 #5 0x00007ffff75722c8 in ?? () from /lib/x86_64-linux-gnu/libcrypto.so.3 #6 0x00007ffff765a98f in ?? () from /lib/x86_64-linux-gnu/libcrypto.so.3 #7 0x00007ffff7d51087 in __pthread_once_slow (once_control=0x7ffff7981498, init_routine=0x7ffff765a980) at ./nptl/pthread_once.c:116 ``` the buffer overflow happens in the curl program, not OpenSSL. The strcpy() or similar function (depending on the code you're working with) in curl is the main cause of the vulnerability, and OpenSSL just happens to be part of the stack trace because curl uses OpenSSL for cryptographic functions. **Registers at the Breakpoint:** At the point where the overflow occurs, checking the CPU registers, which show that the `rip` (Instruction Pointer) is at `0x7ffff7e31b80`, inside the `__strcpy_evex` function. Here's the relevant register information: ``` rax 0x472cf0 4664560 rbx 0x7ffff7832be3 140737345956835 rcx 0x472cf0 4664560 rdx 0x472cf0 4664560 rsi 0x7ffff7832be3 14073734595 …

Source code

src/tool_main.clines 227–287 · definition of main
227int main(int argc, char *argv[])
C1: Provided curl source (main function) shows no strcpy usage. The stack trace in the report shows __strcpy_evex called from CRYPTO_strdup in libcrypto.so.3 (OpenSSL), not from curl code.
C3: No code path from curl command-line arguments or configuration to the OpenSSL module loading function is shown in the provided source.
228#endif
229{
230 CURLcode result = CURLE_OK;
231 struct GlobalConfig global;
232 memset(&global, 0, sizeof(global));
233
234 tool_init_stderr();
235
236#ifdef _WIN32
237 /* Undocumented diagnostic option to list the full paths of all loaded
238 modules. This is purposely pre-init. */
239 if(argc == 2 && !_tcscmp(argv[1], _T("--dump-module-paths"))) {
240 struct curl_slist *item, *head = GetLoadedModulePaths();
241 for(item = head; item; item = item->next)
242 printf("%s\n", item->data);
243 curl_slist_free_all(head);
244 return head ? 0 : 1;
245 }
246 /* win32_init must be called before other init routines. */
247 result = win32_init();
248 if(result) {
249 errorf(&global, "(%d) Windows-specific init failed", result);
250 return (int)result;
251 }
252#endif
253
254 if(main_checkfds()) {
255 errorf(&global, "out of file descriptors");
256 return CURLE_FAILED_INIT;
257 }
258
259#if defined(HAVE_SIGNAL) && defined(SIGPIPE)
260 (void)signal(SIGPIPE, SIG_IGN);
261#endif
262
263 /* Initialize memory tracking */
264 memory_tracking_init();
265
266 /* Initialize the curl library - do not call any libcurl functions before
267 this point */
268 result = main_init(&global);
269 if(!result) {
270 /* Start our curl operation */
271 result = operate(&global, argc, argv);
272
273 /* Perform the main cleanup */
274 main_free(&global);
275 }
276
277#ifdef _WIN32
278 /* Flush buffers of all streams opened in write or update mode */
279 fflush(NULL);
280#endif
281
282#ifdef __VMS
283 vms_special_exit(result, vms_show);
284#else
285 return (int)result;
286#endif
287}