CPE dns hijacking malware

Tue Nov 12 06:17:51 UTC 2013

On 11/12/2013 1:12 AM, Dobbins, Roland wrote:
> On Nov 12, 2013, at 12:56 PM, Mike <mike-nanog at tiedyenetworks.com> wrote:
>
>> It appears that some of my subscribers DSL modems (which are acting as nat routers) have had their dns settings hijacked and presumably for serving ads or some such nonsense. 
> How do you think this was accomplished?  Via some kind of Web exploit customized for those devices and targeting your user population via email or social media, which tricked users into clicking on something that accessed the Web admin interface via default admin credentials or somsesuch; or via some direct attack on the CPE devices themselves; or via some other method?

Basically two cases...  (1) XSS attack on the router using default (or
dictionary) credentials to set the DNS server on the router, or (2) DHCP
hijacking daemon installed on the client, supplying the hijacker's DNS
servers on a DHCP renewal.  Have seen both, the latter being more
common, and the latter will expand across the entire home subnet in time
(based on your lease interval)

Jeff