Security Experts:

Los Angeles County Notifies 756,000 of Data Breach

A 'mere' 10.8% phishing success rate has forced Los Angeles County to notify approximately 756,000 individuals that their personal information may have been compromised. The attack occurred on May 13, 2016 when 1,000 County employees received phishing emails. 108 employees were successfully phished.

Many large organizations would welcome a 10% success rate in their internal anti-phishing training sessions, with 30% and above being common. The 2016 Verizon DBIR suggests that 30% of all phishing emails are opened. The high number of individuals affected from a relatively low number of successes in LA County demonstrates how dangerous phishing attacks can be.

The nature of the potentially compromised information is also concerning. "That information may have included first and last names, dates of birth, Social Security numbers, driver's license or state identification numbers, payment card information, bank account information, home addresses, phone numbers, and/or medical information, such as Medi-Cal or insurance carrier identification numbers, diagnosis, treatment history, or medical record numbers," said the County of Los Angeles Chief Executive Office in a statement released Friday.

Personal information is prized by criminals. While it is relatively easy to change passwords and bank and card details, it is less easy to change other personal data that can lead to identity theft in the future. In this instance it seems that both were potentially compromised.

The individuals potentially compromised would have been through their contact with the Assessor, Chief Executive Office, Children and Family Services, Child Support Services, Health Services, Human Resources, Internal Services, Mental Health, Probation, Public Health, Public Library, Public Social Services and Public Works.

It was seven months from compromise to disclosure. County officials took advantage of the exemption from disclosure laws that allows delayed notification if necessary to protect ongoing legal investigations. "At the direction of the District Attorney's Office," explained the statement, "notification of the potentially affected individuals was delayed to protect the confidentiality of the sensitive, ongoing investigation and prevent broader public harm. Law enforcement agencies are authorized to request such exemptions to notification requirements."

Also on Friday, the LA County DA's office announced that it had completed a 'lengthy and complex' investigation into the incident, and has now filed charges against Austin Kelvin Onaghinor, a 37-year old Nigerian national. Onaghinor's current whereabouts was not stated, although he is not yet in custody. "My office will work aggressively to bring this criminal hacker and others to Los Angeles County where they will be prosecuted to the fullest extent of the law," said District Attorney Jackie Lacey.

The arrest warrant charges Onaghinor with nine counts including unauthorized computer access and identity theft. 

The DA CIRT investigating the incident has been operating for three years, and has already investigated 85 cyber cases. Its work has led to several successful convictions and restitution of nearly $4 million. "In this instance," says the DA's statement, "the team responded to the security breach, identified the source of the cyber-intrusion and thwarted Onaghinor's attack. If convicted as charged, the defendant faces a maximum possible sentence of 13 years in state prison."

The County has established a website providing more information. It is offering free identity monitoring for potentially affected individuals, including credit monitoring, identity consultation and identity restoration. It adds, "Based on intensive investigation and monitoring, there is no evidence that confidential information from any members of the public has been released because of the breach."

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Kevin Townsend is a Senior Contributor at SecurityWeek. He has been writing about high tech issues since before the birth of Microsoft. For the last 15 years he has specialized in information security; and has had many thousands of articles published in dozens of different magazines – from The Times and the Financial Times to current and long-gone computer magazines.