Comment Crew, China-based group of hackers is changing tactics

Pierluigi Paganini June 27, 2013

Chinese hackers Comment Crew is changing tactics, security firms suspected it due the analysis of principal cyber espionage campaigns targeted their clients.

The Comment Crew is back again, security experts suspect the involvement of the Chinese group of hackers in the cyber dispute between U.S. and China.  In February The Mandiant Intelligence Center™ released an interesting report that revealed an enterprise-scale computer espionage campaign dubbed APT1.  The term APT1 is referred to one of the numerous cyber espionage campaign that stole the major quantity of information all over the world.  Various security firms had monitored the group during last years and report details its operations.

Comment Crew Mandiant

Senior researcher at FireEye. Alex Lanstein sustains that The Comment Crew is still working undercover after an apparent period of rest:

“They took a little breather, and they started back up,” he said.

Security researchers noted that after the intense activities observed early 2013 the group stopped using its infrastructures and suspended attack the previous targets. It was a wrong conviction, probably the hackers belonging to The Comment Crew group started new campaigns against new and old targets from different infrastructures.

“We didn’t see them take control of any of the systems they had previously compromised,” “They started fresh with a whole new round of attacks.” Lanstein revealed.

The Mandiant’s report blamed the Chinese military unit called “61398” for a series of cyber attacks that compromised 141 organizations in seven years. The Mandiant Intelligence Center identified a common pattern for the attacks originated from Chinese sources defining also a series of key indicators for identifying ongoing APT attacks.

The Comment Crew is in reality a group of state-sponsored hackers operating following an identified scheme, sharing tools and methods during the attacks that hit various organizations and companies with a cyber espionage purpose.

The researchers used to track malware campaigns analyzing tracks left by hackers including keyboard layouts and the presence of embedded fonts and abuse of bogus DNS (domain name system) registration details.

Lanstein continued the discussion evidencing that FireEye security firm discovered another curious proof during its investigation. The Comment Crew group left the name of their particular coding project, called “Moonclient,” in many instances of the malware detected. Lanstein commented on the forgetfulness of hackers with the following words:

“you are dealing with humans on the other side of the keyboard,” “This is a mistake made over and over again,”

FireEye kept this information secret to avoid allow its team to follow the Comment Crew but it seems now it seems they have changed tactics and malware.

“It’s more difficult to track them now,” Lanstein said.

FireEye has released today an interesting report titled “Digital Bread Crumbs: Seven Clues To Identifying Who’s Behind Advanced Cyber Attacks ” that explains how to conduct an investigation based on common errors committed by the hackers.

The document is based on the analysis of nearly 1,500 campaigns tracked by FireEye, the paper reported the results of the study on the common characteristics of various attack and the way to identify the hackers:

  • Keyboard Layout. Hidden in phishing attempts is information about the attacker’s choice of keyboard, which varies by language and region.
  • Malware Metadata. Malware source code contains technical details that suggest the attacker’s language, location, and ties to other campaigns.
  • Embedded Fonts. The fonts used in phishing emails point to the origin of the attack. This is true even when the fonts are not normally used in the attacker’s native language. 
  • DNS Registration. Domains used in attacks pinpoint the attacker’s location. Duplicate registration information can tie multiple domains to a common culprit.
  • Language. Language artifacts embedded in malware often point to the attacker’s country of origin and common language mistakes in phishing emails can sometimes be reverse-engineered to determine the writer’s native language.
  • Remote Administration Tool Configuration. Popular malware-creation tools include a bevy of configuration options. These options are often unique to the attacker using the tool, allowing researchers to tie disparate attacks to a common threat actor.
  • Behavior. Behavioral patterns such as methods and targets give away some of the attacker’s methods and motives.

As highlighted in the report for a security firm and for the victims of the attacks it is fundamental to recognize the evidence of ongoing attack and the real origin of the offending. A targeted organization could use the knowledge on methods and objective of the attack for:
• Immediately shift resources to bolster vulnerable data
• Enlist additional help, whether internal resources or law enforcement
• More closely examine other vectors—possibly overlooked—that have been used by the attackers other campaigns

The cyber threats are events even more sophisticated, the attackers adopt complex techniques that evolve with time … it is necessary a smart defense based also on the study of principal campaigns.

Pierluigi Paganini

(Security Affairs – Cyber espionage, Comment Crew)

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