full-disclosure - Re: Cisco IOS Denial of Service that affects most Cisco IOS routers- requires power cycle to recover

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

From: lee.e.rian at census.gov (lee.e.rian@...sus.gov)
Subject: Re: Cisco IOS Denial of Service  that affects most
 Cisco IOS routers- requires power cycle to recover

On July 22 Curt Purdy <purdy@...man.com> said
>
> If the packet expires in transit i.e. ttl 1 to router 2 hops away means
it
> never gets to that router.  Not possible to fill a queue with a packet
that
> is dropped by the previous router.

Someone said that having the TTL of an evil packet expire on a vulnerable
router was enough to cause the problem.  The reasoning made sense - the TTL
expires so the packet gets bumped up to process level, put on the input
queue and never comes off.  But I haven't been able to duplicate that and
was wondering if it was a bogus report or my testing was ummm... less that
perfect.

So... has anyone been able to verify that the problem occurs when the TTL
expires without the packet being addressed to the router?  Or is it a
requirement that the evil packet be addressed to the router?

Regards,
Lee