China-Based Cyber Espionage Group Reportedly Behind Breach at Mitsubishi Electric

A data breach at Japan's Mitsubishi Electric that may have exposed some 200 MB of personal and confidential business data is the latest reminder of the growing threat many organizations face from sophisticated cyber espionage groups.

Mitsubishi on Monday admitted it had experienced a data breach last June after at least two Japanese newspapers reported on the incident this week. In an emailed statement to Dark Reading, the company said it detected the incident on June 28, 2019, and took immediate measures to limit damage.

"Mitsubishi Electric acknowledges the possibility of personal and confidential information leakages due to unauthorized access to the company's cyber networks," the statement said.

The company, whose customers include major government, defense, and private-sector organizations, did not offer any details on the kinds of information that might have been compromised or how extensive the damage might have been. But it said that no sensitive information belonging to critical infrastructure organizations in the defense, power, electric, and railway sectors were leaked.

The Asahi Shimbun, one of the first to report on the breach, on Tuesday said data belonging to 8,122 individuals might have been exposed since last June. The potentially leaked information included names and other personal data belonging to over 4,560 employees at the company's headquarters, as well as nearly 2,000 new graduates who joined the company between 2017 and April 2019, and several mid-career employees and retirees.

In addition, the intruders appear to have had access to data on more than 10 government customers of Mitsubishi Electric and dozens of other businesses, including those in critical infrastructure sectors, Asahi Shimbun said, citing officials it said were close to the investigation. The data that was exposed included that pertaining to business negotiations, joint development activity, product orders, and company meeting materials.

According to the newspaper, while Mitsubishi Electric informed Japan's Defense Ministry about the attack last August, many of the company's partners in the private sector, including leading electric utilities, railway operators, and financial companies, were kept in the dark until this week.

"The company appears to be contacting only business partners whose information might have been significantly compromised, but it is still not giving the entire picture of the breach," the paper said.

Earlier, Asahi Shimbun and Nikkei both cited unnamed company officials as saying scores of servers and PCs across Mitsubishi Electric's office in Japan and China had been compromised in the attack. Both newspapers identified the group behind the attack as "Tick', a China-based outfit that some security vendors also have referred to as Bronze Butler and REDBALDKNIGHT.

Hijacked Account
The attack is thought to have begun with the misuse of a single compromised user account belonging to a Mitsubishi Electric affiliate in China. The hijacked account was used to infiltrate systems at most of Mitsubishi Electric's major facilities, including its sales headquarters, its electronic systems business headquarters, and its head office, Asahi Shimbun said.

Researchers at Trend Micro and Secureworks have previously described Tick/Bronze Butler/REDBALDKNIGHT as a China-based cyber espionage group with a special focus on Japanese targets.

According to Secureworks, the group has long been focused on stealing intellectual property and other confidential business data from Japanese organizations, especially those in critical infrastructure sectors. Like many groups, Tick employs spear-phishing and strategic Web compromises to gain an initial foothold on a target network.

Trend Micro has said it discovered evidence of Tick targeting South Korean, Russian, and Singaporean organizations in addition to Japanese-based firms. The security vendor has described Tick operators as using steganography and other techniques to deploy and embed its malware on target systems.

Ben Goodman, senior vice president at ForgeRock, says attacks involving the abuse of legitimate user accounts highlight the need for a zero-trust approach to security. "A zero-trust approach means that organizations no longer treat people, devices, and services communicating on the corporate network as if they are good actors deserving of greater trust," he says.

Instead, all access requests are authenticated and authorized as if they are from an unknown user from an untrusted network. "By looking closer at what access users have and how they are using that access, we can better understand where some may have more access than they require," Goodman says.

Forcing users to authenticate and authorize to all of their applications and services also can enable a better understanding of normal user activity and detection of potentially abnormal behavior, he says.

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