The Domain Name Service (DNS) is one of the most important components in 
networking infrastructure, enabling users and services to access applications by 
translating URLs (names) into IP addresses (numbers). Because every icon and URL 
and all embedded content on a website requires a DNS lookup, loading complex 
sites necessitates hundreds of DNS queries. 
And because of that, DNS is a precious target and only lags behind http as 
the most targeted protocol. 
DDoS-ing DNS is an effective way to make the service unavailable. As the 
flood of malicious DNS requests hit the infrastructure, the service can become 
unresponsive if there is not enough capacity. Organizations can add more servers 
or turn to their cloud-based security provider for help. One of the strategies 
cloud-based security providers use to shield DNS is DNS redirection. Cloud 
providers will divert incoming traffic to their own infrastructure, which is 
resilient enough to detect and absorb these attacks. The success of this 
strategy however depends on how well the website's original IP address can be 
shielded. If the bad guy can find that IP address, then they can get around the 
protection.
So is DNS redirection effective? 
Researchers 
decided to find out.
Scientists from 
KU Leuven in 
Belgium built a tool called 
CLOUDPIERCER, which automatically tries to 
retrieve websites' original IP address, including the use of unprotected 
subdomains. Almost 18,000 websites, protected by five different providers, were 
part to the team's DNS redirection vulnerability tests. In more than 70% of the 
cases, CLOUDPIERCER was able to retrieve the website's original IP address - the 
precise info needed to launch a successful attack.
Researchers did share their findings with those cloud-based providers and 
have made 
CLOUDPIERCER freely available 
for organizations to test their own DNS infrastructure.
In another DNS scam, a new version of the 
NewPosThings 
PoS (point of sale, not…) malware is using DNS rather than http/https/ftp to 
extract data from infected PoS terminals. This is an interesting twist since 
most security solutions monitor http/https traffic for suspicious activity. 
Anti-virus doesn’t necessarily watch DNS and admins cannot simply turn off DNS 
since they need it to resolve hostnames and domains. Seems like a clear 
shot.
The newest version of NewPoSThings is nicknamed 
MULTIGRAIN 
and it only targets (and infects) one specific type of PoS platform: The 
multi.exe process, specific to a popular electronic draft capture software 
package. If the multi.exe process is not found the malware moves on. Once 
inside, the malware waits for the Track 2 credit card data and once it has the 
data, it encrypts and encodes it before sending to the bad guy via a DNS 
query.
The use of DNS for data exfiltration on PoS devices is not new and shows not 
only how attackers can adjust to different environments but also, that 
organizations need to be more aware of their DNS traffic for potential 
anomalies. 
BIG-IP could also 
help in both instances.
For the redirection issue, BIG-IP or our 
Silverline Managed 
Service offers Proxy mode with DNS redirection. With Routed Mode, we offer 
BGP to Silverline then Generic Routing Encapsulation (GRE) tunnels or L2VPN back 
to the customer to mask the original IP address.
For the PoS malware, BIG-IP can utilize a DNS response policy zone (RPZ) as a 
firewall or outbound domain filtering mechanism. An RPZ is a zone that contains 
a list of known malicious Internet domains. The list includes a resource record 
set (RRset) for each malicious domain and each RRset includes the names of the 
malicious domain and any subdomains of the domain.
When the BIG-IP system receives a DNS query for a domain that is on the 
malicious domain list of the RPZ, the system responds in one of two ways based 
on your configuration. 
You 
can configure the system to return an NXDOMAIN record that indicates that 
the domain does not exist or return a response that directs the user to a walled 
garden.
BIG-IP returns NXDOMAIN response to DNS query for malicious 
domain
BIG-IP forwards DNS query for malicious domain to walled 
garden
DNS is one of those technologies that is so crucial for a functioning 
internet, especially for human interaction. Yet is often overlooked or seems to 
only get attention when things are broken. Maybe take a gander today to make 
sure your DNS infrastructure is secure, scalable and ready to answer each and 
every query. Ignoring DNS can have grave consequences.
ps
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