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Re: RLA ("Remote LanD Attack")

From: Synister Syntax <synistersyntaxlist () gmail com>
Date: Thu, 15 Dec 2005 17:36:44 -0500
     Not a problem at all Roger.  I agree, its a bit shocking, by I am
far less concerned about the Cisco devices and/or business networks. 
What I am concerned over is consumer grade products, that do not
enforce all the RFC's.  That lack security against spoofed packets,
and spoofed internal address on the external interface.  Network
administrators for business will usually have such a rule set that
will keep them from being vulnerable of such an attack, if not, I hope
they will now set a rule, but Joe Smith and his $15 Verizon router
will have no clue what a packet is, let alone the RFC's.  With such
devices being susceptible to attack, and with the delay in user
patches, or firmware updates.

     I think it is such users we need to worry about, they have no
recourse.  The devices will shut off.  That's why I am hoping that the
vendors will release patches/updates.

     As far as Win2K3, again, I am not sure, it was brought up in a
privet email about this exploit.  And it was simply brought up to see
if what I released was related to that CVE.  Of course they are
related in the fact they are LanD attacks, but mine is different in
many ways, (one, mines remote [outside networks], and two, my exploit
is for devices only).  I do not have a of Win2K3 to even test.  Sorry
if bringing it up has cause any more confusion.

     By all means, if you have any further questions, I would be glad
to answer them.  Again, thanks for your input and interests.

Thanks...

On 12/15/05, Roger A. Grimes <roger () banneretcs com> wrote:

I appreciate you writing back. I'm not quarreling with what you wrote. A
LAND attack being successful on a Cisco device is quite surprising.  I
tried a Syn LAND attack on my W2K3 server without WF enabled and it
didn't do anything. I'm not sure what that reference is referring to.

-----Original Message-----
From: Synister Syntax [mailto:synistersyntaxlist () gmail com]
Sent: Thursday, December 15, 2005 5:11 PM
To: Roger A. Grimes
Subject: Re: RLA ("Remote LanD Attack")

     Here is the CVE I was referring to:  *CVE-2005-0688*
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0688

     Again, my exploit has nothing to do with the CVE (MS Windows 2K3)
exploit, and I am in no way stating such systems are susceptible.  My
reports are about Network Devices, namely Border/Perimeter devices
(Routers, Modems, Switches, Firewalls).  Hope this helps.

Thanks...

On 12/15/05, Roger A. Grimes <roger () banneretcs com> wrote:

I just tried it against W2K3 SP1 and it does not work. I don't have a
non-SP1 version to check at the moment.

-----Original Message-----
From: Synister Syntax [mailto:synistersyntaxlist () gmail com]
Sent: Thursday, December 15, 2005 2:32 PM
To: Roger A. Grimes
Subject: Re: RLA ("Remote LanD Attack")

     Sorry had a few spelling errors...

Fixed below....

"  That is correct this affects network perimeter devices, such as
routers, switches, etc.  This is not an accountant about an OS

exploit.

Although Microsoft only recently patched the initial exploit, it is
patched for both external and internal attacks.
Windows 2003 may still be susceptible to such an attack, however that
is a different post, under CVE investigation, this has nothing to do
with such an exploit.

    I used the -k switch a few, times although, it seemed to work
either way.  Although, to make sure it works, it would be best to use
such a switch.  Also, I wanted to point out, using the -d switch and
increasing the data/payload size seems to cause the attack to be more

optimized.

Works faster in some cases.  It will work either way.
--
Regards,
SynSyn
Network Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)"

On 12/15/05, Synister Syntax <synistersyntaxlist () gmail com> wrote:

     That is correct this affects network perminter devices, such as



routers, switches, etc.  This is not an accounment about an OS
exploit.  Although Microsoft only recently patched the initial
exploit, it is patched for both external and internal attacks.
Windows 2003 may still be susecpitble to such an attack, however
that is a diffrent post, under CVE invesigation, this has nothing to



do with such an exploit.

     I used the -k switch a few, times although, it seemed to work
eitherway.  Although, to make sure it workes, it would be best to
use such a switch.  Also, I wanted to point out, using the -d switch



and increaseing the data/payload size seems to cause the attack to
be more



optimiozed.  Workes faster in some cases.  It will work eitherway.

On 12/15/05, Roger A. Grimes <roger () banneretcs com> wrote:

Just to clarify, so that people don't think this affects Windows
XP

SP2.

I've tested SP2 again, and the LAND attack no longer works. This
announcement concerns gateway network devices that computers may
attach to (the announcement is a little confusing at first).

Also, to pull off the hping2 example, you'll need the -k parameter



to make sure the source port stays at port 80, else it will
increment up (80, 81, 82, etc.)

Roger

******************************************************************
* *Roger A. Grimes, Banneret Computer Security, Consultant *CPA,
CISSP, MCSE: Security (2000/2003/MVP), CEH, yada...yada...
*email: roger () banneretcs com
*Author of Honeypots for Windows (Apress)
*http://www.apress.com/book/bookDisplay.html?bID=281
******************************************************************
*


-----Original Message-----
From: Synister Syntax [mailto:synistersyntaxlist () gmail com]
Sent: Wednesday, December 14, 2005 1:49 AM
To: bugtraq () securityfocus com; full-disclosure () lists grok org uk;
vuln-dev () securityfocus com; NTBUGTRAQ () listserv ntbugtraq com
Subject: RLA ("Remote LanD Attack")

Below is a copy of my RLA exploit submission in ASCII.  Attached
is a MSWord (.doc) version with rich formatting, created with ease



of view in mind.

Regards...

----------

RLA
("Remote LanD Attack")
2005


As discovered by:
 Justin M. Wray
(jayizkool () gmail com)


Devices/Vendors Vulnerable:
- Microsoft Windows XP, SP1 and SP2
- Linksys Routers
- Westell Routers/Modems
- Motorola Modems/Routers
- Cisco Firewalls, Switches, and Routers
- DSL Modems
- Cable Modems
- Consumer Routers
- All Central Connectivity Devices (any manufacturer)

Devices/Vendors Tested:
- Linksys BEFW11S4
- Linksys WRT54GS
- Westell  Versalink 327W (Verizon Modem)
- Cisco Catalyst Series (Multiple)
- Scientific Atlantic DPX2100 (Comcast Modem)

Definition:
A LAND attack is a DoS (Denial of Service) attack that consists of



sending a special poison spoofed packet to a computer, causing it
to



lock up. The security flaw was first discovered in 1997 by someone



using the alias "m3lt", and has resurfaced many years later in
operating systems such as Windows Server 2003 and Windows XP SP2.
(http://en.wikipedia.org/wiki/LAND_attack)

Explanation of LanD:
LanD uses a specially crafted ICMP  echo packet which has the same



source and destination address.  The receiving system stalls due
to the erroneous packet and not having instructions to handle the
unique packet.  In Windows 9x  variants, the systems will "blue
screen. "  On modern NT  variants, the systems will hang for
approximately 30 seconds with full CPU usage before discarding the



packet.  With a looped script, the attacker can render the system
useless.  UNIX variants have been able to use a firewall rule to
drop LanD packets - leaving most systems patched.

Microsoft originally released an initial patch that secured
Windows 9x variants - causing the exploit to lose popularity and
become somewhat obscure.  Later, when Windows NT variants were
released, Microsoft neglected to patch the security flaw; this
caused Windows XP Service Pack 2 to remain susceptible to such an
attack.  Within the last four
(4) months, Microsoft has released a patch for Windows NT

variants.


LanD versus Remote LanD:
LanD was originally introduced in the late 1990s and was very
popular with educational and business networks.  The original LanD



attack had to be executed internally on the local network -
thereby giving rise to the name "LanD" (indicating that access has



been granted to the local premises).  However, with a remote
attack (Remote LanD), crafting special packets and spoofing the
destination



and source IP addresses will cause the attack to be carried out
remotely against the central connectivity device.

Exploit / Proof of Concept:
There is no handwritten code needed to exploit this vulnerability.
The only requirement is an IP packet creation utility (such as
HPing2 or IPSorcery). Below are some HPing2 examples:
                Victim's IP Address: 63.24.122.59
                Victim's Router IP Address: 192.168.1.1
                hping2 -A -S -P -U 63.24.122.59 -s 80 -p 80 -a
192.168.1.1

Remote LanD Specifications:
Although the exploit will work without the Ack, Syn, Push, and Urg



(flags), the device does not seem to shut off without these flags.
Sending just the LanD part of the packet seems to only create high



amounts of latency on the victim's end.  The spoofed source
address must be the address of the central connectivity device;
although the



normal default is 192.168.1.1, some manufacturers use different
addresses (such as 192.168.1.100 or 192.168.0.1).  As a result,
the IP address should be checked prior to initiating any test.
Additionally, a broadcast address will work for a source address
as well, thereby flooding the network with responses from all the
machines connected to the network.  Although it will not stale the



Central Connectivity Device, it will maximize the entire network
usage - crippling the network with extremely high latency.

Test Environment:

- Test One
  - Attacker:  hping2 on Comcast Cable connection behind Linksys

Router

  - Victim:  DSL Modem/Router on Verizon DSL connection

- Test Two
  - Attacker:  hping2 on Comcast Cable connection behind Linksys

Router

  - Victim:  Linksys Router on Comcast Cable connection

- Test Three
  - Attacker:  hping2 on Comcast connection behind Linksys Router
  - Victim:  Comcast Cable Modem

- Test Four
  - Attacker:  hping2 on Comcast connection behind Linksys Router
  - Victim:  Cisco Router on T1 connection

- Test Five
  - Attacker:  hping2 on Comcast connection behind Linksys Router
  - Victim:  Cisco Pix Firewall, on T1 connection

Test Results:

Test One:
Connection Latency - followed by the modem physically turning off.
Time elapsed: approximately 10 seconds (from beginning of packet
flooding to complete shutdown).

Test Two:
Connection Latency, router reset, then connection lost.  Reset
needed before router would communicate online again.

Test Three:
Modem lights flickered; the modem lost connection and sat with the



Data light completely out.

Test Four:
Router lost connection to the internet.

Test Five:
Firewall lost network connection.
Conclusion:
It appears that central connectivity device manufacturers need to
release firmware updates and/or patches to protect against LanD
and remote LanD attacks. The LanD attack is no longer simply a
local attack but has now evolved into having the capability of
being launched remotely.

Acknowledgements:
- Casey O'Brien, M.S.
  - Assisted with test trials
- Matthew Wines
  - Assisted with test trials
- Yvonne M. Wray, M.S.
  - Report editor

Submitted: 12/14/2005 by Justin M. Wray

--
Regards,
SynSyn
Netowork Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)




--
Regards,
SynSyn
Network Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)




--
Regards,
SynSyn
Network Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)




--
Regards,
SynSyn
Network Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)




--
Regards,
SynSyn
Network Manager, Server Administrator, Security Specialist
(http://www.teamtrinix.com)
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