Info

Last Modified

5 months ago

Percent Complete

100%

Disclosure

Sep 02, 2004

Discovery

Unknown

Dates

Exploit

Sep 11, 2004

Solution

Unknown

Description

Apache contains a flaw that may allow a remote denial of service. The issue is triggered when a remote attacker aborts an SSL connection in a particular state causing an infinite loop to occur. The flaw occurs in ssl_engine_io.c when using a RewriteRule to do reverse proxying to an SSL server.

Classification

Location: Remote/Network Access Required
Attack Type: Denial of Service
Impact: Loss of Availability
Exploit: Exploit Available
Disclosure: OSVDB Verified

Solution

Currently, there are no known upgrades or patches to correct this issue. It is possible to correct the flaw by implementing the following workaround:

1. Disable mod_ssl in your Apache configuration file.

2. If your running one of the Redhat Enterprise Operating Systems, you can apply an appropriate RPM from: RHSA link above.

3. There's a workaround available from CVS. It has not been tested and should be considered unstable:

--- httpd-2.0/modules/ssl/ssl_engine_io.c 2004/07/13 18:11:22 1.124
+++ httpd-2.0/modules/ssl/ssl_engine_io.c 2004/08/11 13:19:24 1.125
@@ -589,6 +589,10 @@
while (1) {

if (!inctx->filter_ctx->pssl) {
+ /* Ensure a non-zero error code is returned */
+ if (inctx->rc == APR_SUCCESS) {
+ inctx->rc = APR_EGENERAL;
+ }
break;
}