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[Sun][Other] Schwachstelle im Sun ONE/IPlanet Web Server - Sun Alert 50603
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Liebe Kolleginnen und Kollegen,
soeben erreichte uns das nachfolgende Bulletin des SUN Customer
Warning System ueber unsere Kollegen von UNIRAS. Wir geben diese
Informationen unveraendert an Sie weiter.
CERT/CC VU#867593
Die HTTP TRACE Methode wird benutzt, um fuer Debugging Zwecke den
Inhalt eines Client-Requests im Entity Body einer HTML-Message
zurueckzugeben.
Angreifer, die einen Web-Server kontrollieren, koennen dieses
Verfahren dazu missbrauchen, um Zugang zu vertraulichen Daten, wie
Cookies oder Authentifikationsdaten (Username, Passwort) zu
erlangen, die im HTTP-Request (an andere Web-Server) uebertragen
werden. Dazu muessen aber zusaetzliche, sog. "Cross Domain" Schwach-
stellen im Browser des Clients vorhanden sein (vgl. CERT/CC
VU#244729, VU#711843, VU#728563), um die Daten auslesen zu koennen.
Dies ist z.B. beim MS Internet Explorer der Fall. Die Angriffs-
technik als Ganzes wird als "Cross Site Tracing" bezeichnet.
Auch der Sun ONE/IPlanet Web-Server unterstuetzt HTTP TRACE und kann
damit fuer Angriffe missbraucht werden.
Betroffen von dieser Schwachstelle sind Sun ONE/iPlanet Web Server
4.1, Service Pack 1 - 12 und Sun ONE/iPlanet Web Server 6.0, Service
Pack 1 - 5. Da es sich streng genommen, nicht um eine Schwachstelle
des Servers handelt, stellt Sun keine Patches bereit, sondern folgt
der CERT/CC Empfehlung, den HTTP TRACE Support im Web-Server zu
unterbinden.
Fuer Sun ONE Web Server 6.0 SP2 und aufwaerts:
i) Folgende Anweisungen in obj.conf hinzufuegen:
<Client method="TRACE">
AuthTrans fn="set-variable" remove-headers="transfer-encoding"
set-headers="content-length: -1" error="501"
</Client>
ii) Danach den Web-Server neu starten
Fuer Sun ONE Web Server vor Version to 6.0 SP2:
i) Legen sie eine Datei reject_trace.c mit folgenden Inhalt an:
----------------------------- start --------------------------------
#include "nsapi.h"
NSAPI_PUBLIC int reject_trace(pblock *pb, Session *sn, Request *rq)
{
const char *method;
method = pblock_findval("method", rq->reqpb);
if (method && !strcmp(method, "TRACE")) {
/* * Set a bogus content length so the TRACE handler
* will refuse tohandle the request
*/
param_free(pblock_remove("transfer-encoding",rq->headers));
param_free(pblock_remove("content-length", rq->headers));
pblock_nvinsert("content-length", "-1", rq->headers);
log_error(LOG_WARN, "reject-trace", sn, rq,
"rejecting TRACE request");
protocol_status(sn, rq, PROTOCOL_NOT_IMPLEMENTED, NULL);
return REQ_ABORTED;
}
return REQ_NOACTION;
}
----------------------- end --------------------------------
ii) Uebersetzen sie die NSAPI neu. Anleitungen finden Sie hier:
http://docs.sun.com/source/816-5686-10/04_mysaf.htm#15053(6.x)
http://docs.sun.com/source/816-5673-10/04_mysaf.htm#15053(4.x)
iii) Fuer Sun ONE/iPlanet Web Server 6.0 RTM und 6.0 SP1, fuegen
Sie am Ende von magnus.conf folgende Anweisung ein:
Init fn="load-modules" shlib="<path to library>/
reject_trace.so"funcs="reject_trace"
Fuegen Sie folgende Anweisung in obj.conf nach
<Object name="default"> ein:
AuthTrans fn="reject_trace"
iv) Fuer Sun ONE/iPlanet Web Server 4.1 Service Pack 1 - 12 fuegen
Sie folgende Anweisung zu obj.conf am Ende der Init Section
hinzu:
Init fn="load-modules" shlib="<path to library>/
reject_trace.so"funcs="reject_trace"
Fuegen Sie folgende Anweisung in obj.conf nach
<Object name="default"> ein:
AuthTrans fn="reject_trace"
Das DFN-CERT bietet einen Mirror der Patches von Sun unter
ftp://ftp.cert.dfn.de/pub/vendor/sun/patches
an.
(c) der deutschen Zusammenfassung bei DFN-CERT Services GmbH; die
Verbreitung, auch auszugsweise, ist nur unter Hinweis auf den Urheber,
DFN-CERT Services GmbH, und nur zu nicht kommerziellen Zwecken gestattet.
Mit freundlichen Gruessen,
Klaus Moeller, DFN-CERT
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UNIRAS (UK Govt CERT) Briefing Notice - 44/04 dated 04.02.04 Time: 14:00
UNIRAS is part of NISCC(National Infrastructure Security Co-ordination Centre)
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UNIRAS material is also available from its website at www.uniras.gov.uk and
Information about NISCC is available from www.niscc.gov.uk
- - ----------------------------------------------------------------------------------
Title
=====
Sun Security Bulletin:
Sun ONE/iPlanet Web Server Enable HTTP TRACE Method by Default
Detail
======
CERT Vulnerability VU867593 describes a techique to abuse the HTTP TRACE
functionality to gain access to information in HTTP headers. This technique
may be used to access sensitive information in HTTP headers using the HTTP
TRACE method when making HTTP requests to Sun ONE/iPlanet Web Servers.
- - ----------------------------------------------------------------------------------
DOCUMENT ID: 50603
SYNOPSIS: Sun ONE/iPlanet Web Server Enable HTTP TRACE Method by
Default
DETAIL DESCRIPTION:
Sun(sm) Alert Notification
* Sun Alert ID: 50603
* Synopsis: Sun ONE/iPlanet Web Server Enable HTTP TRACE Method by
Default
* Category: Security
* Product: iPlanet Web Server, Sun ONE Web Server
* BugIDs: 4808654
* Avoidance: Workaround
* State: Resolved
* Date Released: 11-Feb-2003
* Date Closed: 11-Feb-2003
* Date Modified: 02-May-2003, 19-May-2003
1. Impact
CERT Vulnerability VU867593 describes a techique to abuse the HTTP
TRACE functionality to gain access to information in HTTP headers.
This technique may be used to access sensitive information in HTTP
headers using the HTTP TRACE method when making HTTP requests to Sun
ONE/iPlanet Web Servers.
This issue is described in the CERT Vulnerability VU#867593 (see
[1]http://www.kb.cert.org/vuls/id/867593).
Note 1: HTTP TRACE, which is part of the HTTP 1.1 standard and
described in RFC 2616, is enabled by default on Sun ONE/iPlanet Web
Servers.
Note 2: Sun ONE/iPlanet Web Servers could be used as an agent to
exploit this issue.
2. Contributing Factors
This issue can occur in the following releases:
* Sun ONE/iPlanet Web Server 4.1 Service Pack 1 through 12
* Sun ONE/iPlanet Web Server 6.0 Service Pack 1 through 5
For supported architectures and OS versions see:
[2]http://wwws.sun.com/software/download/download/5292.html.
3. Symptoms
There are no predictable symptoms that would show the described issue
has been exploited.
SOLUTION SUMMARY:
4. Relief/Workaround
The described issue is not a defect of the Sun ONE/iPlanet Web Server.
However, the following recommendation is provided to avoid this issue.
Disable HTTP TRACE support for SunONE/iPlanet Web Server 4.1 and 6.0
as follows:
* Sun ONE Web Server releases 6.0 SP2 and later:
Add the following to the top of the default object in obj.conf:
<Client method="TRACE">
AuthTrans fn="set-variable" remove-headers="transfer-encoding" set-headers="con
tent-length: -1" error="501"
</Client>
Restart web server
* Sun ONE Web Server releases prior to 6.0 SP2:
Create a file called reject_trace.c and paste the code below into it
----------------------------- start --------------------------------
#include "nsapi.h"
NSAPI_PUBLIC int reject_trace(pblock *pb, Session *sn, Request *rq)
{
const char *method;
method = pblock_findval("method", rq->reqpb);
if (method && !strcmp(method, "TRACE")) {
/* * Set a bogus content length so the TRACE handler will refuse t
o
* handle the request
*/
param_free(pblock_remove("transfer-encoding",rq->headers));
param_free(pblock_remove("content-length", rq->headers));
pblock_nvinsert("content-length", "-1", rq->headers);
log_error(LOG_WARN, "reject-trace", sn, rq, "rejecting TRACE reque
st");
protocol_status(sn, rq, PROTOCOL_NOT_IMPLEMENTED, NULL);
return REQ_ABORTED;
}
return REQ_NOACTION;
}
----------------------- end --------------------------------
Compile the NSAPI:
http://docs.sun.com/source/816-5686-10/04_mysaf.htm#15053(6.x)
http://docs.sun.com/source/816-5673-10/04_mysaf.htm#15053(4.x)
Sun ONE/iPlanet Web Server 6.0 RTM and 6.0 SP1 and add to the end of the magnus
.conf file:
Init fn="load-modules" shlib="<path to library>/reject_trace.so"funcs="
reject_trace"
Then edit the obj.conf file and add the following line after the <Object name="
default"> :
AuthTrans fn="reject_trace"
Sun ONE/iPlanet Web Server 4.1 Service Pack 1 through 12 edit the obj.conf
and add to the end of the Init section:
Init fn="load-modules" shlib="<path to library>/reject_trace.so"funcs="
reject_trace"
Then after the line <Object name="default"> add the following
AuthTrans fn="reject_trace"
Note: The above script is provided "AS IS" and it is the users
responsibility to verify it has been implemented correctly.
5. Resolution
This issue may be addressed by disabling HTTP TRACE as shown above in
the Relief/Workaround section.
Change History
02-May-2003:
* Updated Relief/Workaround section
19-May-2003:
* typos in Relief/Workaround section
This Sun Alert notification is being provided to you on an "AS IS"
basis. This Sun Alert notification may contain information provided by
third parties. The issues described in this Sun Alert notification may
or may not impact your system(s). Sun makes no representations,
warranties, or guarantees as to the information contained herein. ANY
AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT
YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE
OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN.
This Sun Alert notification contains Sun proprietary and confidential
information. It is being provided to you pursuant to the provisions of
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such an agreement, th! e Sun.com Terms of Use. This Sun Alert
notification may only be used for the purposes contemplated by these
agreements.
Copyright 2000-2003 Sun Microsystems, Inc., 4150 Network Circle, Santa
Clara, CA 95054 U.S.A. All rights reserved.
References
1. http://www.kb.cert.org/vuls/id/867593
2. http://wwws.sun.com/software/download/download/5292.html
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UNIRAS wishes to acknowledge the contributions of Sun Microsystems for the
information contained in this Briefing.
- - ----------------------------------------------------------------------------------
This Briefing contains the information released by the original author. Some
of the information may have changed since it was released. If the vulnerability
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<End of UNIRAS Briefing>
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- --
Dipl. Inform. Klaus Moeller (CSIRT) DFN-CERT Services GmbH
https://www.dfn-cert.de/ +49-40-808077-555
PGP RSA/2048, 0BB7C8F9, 6D CC 59 0F 86 0C 58 4D 35 D7 0C 55 EF 4F 42 23
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