A sophisticated group of malware attackers often categorized as "Advanced Persistent Threats" are increasingly using Web services and social networking sites for command and control operations.
An increasing number of sophisticated cyber-criminals are
using social networking sites like Twitter and Facebook to manage targeted
attacks, according to report from security firm Mandiant.
In Mandiant's latest "M-Trends" report, released Jan. 27,
researchers observed more examples of "Advanced Persistent Threats" relying on
social networks and Web-based services, such as Facebook, Google Chat and MSN,
as a command and control mechanism. Attackers are using these networks to host malware
and manage targeted attacks, the report found.
Stealing data is still the top objective of these attackers
and they are beginning to exploit legitimate sites in the same manner as spammers
and mass-malware developers, Mandiant researchers found. Just as worms spread
through Facebook and Twitter by spamming user Wall pages to links to malicious
Web sites and applications, researchers found attackers employed social
networking sites and Web services to launch sophisticated targeted attacks.
Mandiant defines APT as a group of attackers that target the
government, defense organizations, and financial, marketing and research
industries. A type of targeted attack, APT is not a random attack where the
criminals don't care who got caught in their net as long as someone is. APT
attackers have a clear idea of the kind of victims they are looking for. "They
target vulnerable people more often than they target vulnerable systems,"
Mandiant researchers wrote.
Mandiant researchers found a downloader program that used
Facebook's internal messaging feature for C&C activities. Trojans opened
backdoors on to victim computers using MSN and Google Chat for C&C, the
report said. Other backdoor Trojans searched for, parsed, and executed C&C
instructions that were embedded inside HTML comments on compromised Web pages,
such as someone's blog. There was also a malware tool that stole data from the
compromised computer and sent files using Hotmail.
In each of these cases, the attackers' remote activity
looked like normal SSL-encrypted traffic to popular Internet sites, making it
nearly impossible for packet inspection and netflow anomaly analysis tools to
differentiate the malicious from benign activity.
Even as far back as 2009, there was a botnet
which used Twitter
and another botnet
which used Amazon EC2
for remote control. Security experts predicted last
year that more attackers would start using social networking platforms for
command and control because it was easy to
hide their activities in plain sight
. Recently, there were instances of malware
being hosted on the cloud storage
service Rapidshare. According to Mandiant
researchers, the attackers are now doing just that with increasing frequency.
E-mail "spear phishing" seem to be the "weapon of choice"
for establishing a foothold on social networking sites and services, according
to the report. Spear phishing campaigns using infected ZIP, PDF, Word and Excel
files were common. Once the users were compromised, the attackers could launch
more attacks, even several months later, Mandiant said.
According to Mandiant, APT attackers maintain their presence
within a compromised network, and once removed, repeatedly seek to regain
Mandiant said APT attackers will "increasingly leverage the
broad array" of social networking, cloud computing, and online storage sites to
conduct their operations. These services are widely available, can easily be
obtained without sacrificing anonymity and can provide more versatility than a
self-managed attack infrastructure.
Prevention efforts will typically not work against APT, Mandiant said. Instead of trying to stop APT intruders from using legitimate sites to compromise their networks, organizations should make it difficult for the APT intruders to stay in the breached network, ultimately making
them "too expensive" to attack, according to Mandiant.
This is achieved when the security team can determine what the attacker is doing and to anticipate what the attacker will do next, Mandiant said. Organizations need to increase visibility across the enterprise by incorporating specialized monitoring systems that provide host- and network-based visibility, increased logging, and log aggregation, Mandiant said.
Host-based detection tools look for indicators that the host had been compromised as well as signs of the tools, tactics and procedures used by the attacker. These tools can find unknown malware because they aren't looking for actual signatures like a traditional anti-virus, the researchers said. Network-based tools do the same search on network traffic. Mandiant researchers listed nine different logs security managers should be looking at regularly, including internal DNS server logs, DHCP logs, internal Web proxy logs, firewall logs with ingress/egress TCP header information, and external Webmail access logs. Log aggregation tools help managers correlate information from numerous sources, highlight critical information and indexes all information for easy searching. The security team can use all the information to effectively detect and remove the compromised host, repeatedly forcing the attacker to start over to regain control, Mandiant said.