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Re: NTLM buffer overflow

From: Ralph Mitchell <ralphmitchell_at_gmail.com>
Date: Tue, 22 Feb 2005 01:00:06 -0600

It does say: "... in various Unix / Linux vendors implementations of
cURL ...", so maybe they pinged Redhat, Suse, Debian, *BSD, etc, and
got no response?

Ralph

On Mon, 21 Feb 2005 16:17:39 -0800, Dan Fandrich <dan_at_coneharvesters.com> wrote:
> A libcurl buffer overflow has just been reported to BugTraq
> (see http://www.securityfocus.com/archive/1/391042 ). It concerns a stack-
> allocated buffer in the NTLM authentication code that can be overflowed by a
> malicious server. The suggested fix is to allocate the buffer on the heap,
> which translates into a patch like this:
>
> Index: lib/http_ntlm.c
> ===================================================================
> RCS file: /cvsroot/curl/curl/lib/http_ntlm.c,v
> retrieving revision 1.36
> diff -u -r1.36 http_ntlm.c
> --- lib/http_ntlm.c 7 Dec 2004 23:09:41 -0000 1.36
> +++ lib/http_ntlm.c 21 Feb 2005 23:48:00 -0000
> @@ -103,7 +103,6 @@
> header++;
>
> if(checkprefix("NTLM", header)) {
> - unsigned char buffer[256];
> header += strlen("NTLM");
>
> while(*header && isspace((int)*header))
> @@ -124,7 +123,12 @@
> 32 (48) start of data block
> */
>
> - size_t size = Curl_base64_decode(header, (char *)buffer);
> + size_t size;
> + unsigned char *buffer = (unsigned char *)malloc(strlen(header));
> + if (buffer == NULL)
> + return CURLNTLM_BAD;
> +
> + size = Curl_base64_decode(header, (char *)buffer);
>
> ntlm->state = NTLMSTATE_TYPE2; /* we got a type-2 */
>
> @@ -134,6 +138,7 @@
>
> /* at index decimal 20, there's a 32bit NTLM flag field */
>
> + free(buffer);
> }
> else {
> if(ntlm->state >= NTLMSTATE_TYPE1)
>
> The strange part about the advisory is the note "Initial vendor
> notification - No response". That doesn't sound like the Daniel we all
> know and love on this list. If a bug reported here has a two hour
> turnaround time between being reported, discussed and a fix checked in
> (along with an associated test case, of course), then Daniel's having
> a slow day ;-) They obviously didn't try very hard to make contact.
>
> >>> Dan
> --
> http://www.MoveAnnouncer.com The web change of address service
> Let webmasters know that your web site has moved
>
>
>
Received on 2005-02-22

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