This is not a new issue. Juniper issued an advisory for it back in August.


--
Neil J. McRae.
[email protected]
________________________________
From: [email protected] [[email protected]] on 
behalf of Ben Ward [[email protected]]
Sent: 07 November 2011 22:52
To: [email protected]
Subject: Re: [uknof] Widespread JunOS BGP issues today?

Looks like someone's made it public (normally only available via a login):

Source: http://pastebin.com/HBWiH92j

PSN-2011-08-327
View Bulletin PSN-2011-08-327
Title MX Series MPC crash in Ktree::createFourWayNode after BGP UPDATE
Products Affected This issue can affect any MX Series router with port 
concentrators based on the Trio chipset -- such as the MPC or embedded into the 
MX80 -- with active protocol-based route prefix additions/deletions occurring.
Platforms Affected
Security
JUNOS 11.x
MX-series
JUNOS 10.x
SIRT Security Advisory
SIRT Security Notice
Revision Number 1
Issue Date 2011-08-08

PSN Issue :
MPCs (Modular Port Concentrators) installed in an MX Series router may crash 
upon receipt of very specific and unlikely route prefix install/delete actions, 
such as a BGP routing update. The set of route prefix updates is 
non-deterministic and exceedingly unlikely to occur. Junos versions affected 
include 10.0, 10.1, 10.2, 10.3, 10.4 prior to 10.4R6, and 11.1 prior to 11.1R4. 
The trigger for the MPC crash was determined to be a valid BGP UPDATE received 
from a registered network service provider, although this one UPDATE was 
determined to not be solely responsible for the crashes. A complex sequence of 
preconditions is required to trigger this crash. Both IPv4 and IPv6 routing 
prefix updates can trigger this MPC crash.

There is no indication that this issue was triggered maliciously. Given the 
complexity of conditions required to trigger this issue, the probability of 
exploiting this defect is extremely low.

The assertions (crash) all occurred in the code used to store routing 
information, called Ktree, on the MPC. Due to the order and mix of adds and 
deletes to the tree, certain combinations of address adds and deletes can 
corrupt the data structures within the MPC, which in turn can cause this line 
card crash. The MPC recovers and returns to service quickly, and without 
operator intervention.

This issue only affects MX Series routers with port concentrators based on the 
Trio chipset, such as the MPC or embedded into the MX80. No other product or 
platform is vulnerable to this issue.
Solution:
The Ktree code has been updated and enhanced to ensure that combinations and 
permutations of routing updates will not corrupt the state of the line card. 
Extensive testing has been performed to validate an exceedingly large 
combination and permutation of route prefix additions and deletions.

All Junos OS software releases built on or after 2011-08-03 have fixed this 
specific issue. Releases containing the fix specifically include: 10.0S18, 
10.4R6, 11.1R4, 11.2R1, and all subsequent releases (i.e. all releases built 
after 11.2R1).

This issue is being tracked as PR 610864. While this PR may not be viewable by 
customers, it can be used as a reference when discussing the issue with JTAC.

KB16765 - "In which releases are vulnerabilities fixed?" describes which 
release vulnerabilities are fixed as per our End of Engineering and End of Life 
support policies.

Workarounds
No known workaround exists for this issue.

Thanks to those who replied off-list,

Ben
On 7 November 2011 18:00, Ben Ward 
<[email protected]<mailto:[email protected]>> wrote:
Hi All,

Does anyone have any further information to what was discussed in this thread?

http://mailman.nanog.org/pipermail/nanog/2011-November/041653.html
>From what I can gather there and on Twitter there was a bug which caused 
>Junipers to core dump and either flap all interfaces or reload the BGP process.

Can anyone shed any light on this?

Ben

--
[email protected]<mailto:[email protected]> | 
http://crouchingbadger.com



--
[email protected]<mailto:[email protected]> | 
http://crouchingbadger.com


Reply via email to