U.S. Defense Contractor IEH Corporation Reports Microsoft 365 Cyberattack

IEH Corporation has disclosed a major cybersecurity incident in which a threat actor gained unauthorised access to an employee’s Microsoft 365 mailbox, exposing sensitive company information.

 

Headquartered in Brooklyn, New York, IEH Corporation is a U.S.-based manufacturer of high-performance electronic connectors. The company supplies specialised interconnect solutions for the U.S. defense sector, including connectors used in military aircraft, radar systems, missiles, munitions and other defense equipment.

 

In a filing with the U.S. Securities and Exchange Commission (SEC), IEH Corporation said that it identified a data security incident on August 4, in which a threat actor using an alias gained unauthorized access to an employee’s Microsoft 365 mailbox. Following the incident, IEH Corporation aunched an investigation, with assistance from external cyber security experts, to determine the scope of the incident.

 

The company took immediate measures to contain the incident and terminate the unauthorized access. It also activated its incident response and business continuity procedures and notified the relevant law enforcement authorities.

 

“An investigation determined the compromise originated from a phishing attack in which a malicious actor impersonated a prospective business contact and delivered a hyperlink disguised as a Microsoft document-sharing link. The user accessed the link and entered Microsoft 365 credentials into a fraudulent login page, resulting in unauthorised account access,” IEH Corporation said.

 

The compromised mailbox contained emails, attachments, customer communications, purchase orders, engineering documents and potentially export-controlled technical information. However, IEH said there is no evidence of unauthorised emails being sent or data being exfiltrated, although the information was accessible to the attacker during the breach.

 

“The account was secured, malicious mailbox rules were disabled, evidence was preserved, and corrective actions are underway. Following containment and investigation activities, the Company initiated a review of account security controls and authentication protections applicable to Microsoft 365 services. The Company has already taken and completed a series of corrective actions to contain any impact of the unauthorised access,” IEH Corporation added.

 

IEH Corporation said it has found no evidence that the compromised data was transmitted, downloaded or exfiltrated, although it remained accessible to the attacker during the breach. The company is reviewing the affected communications and will notify impacted parties and regulators if required.