Now that we're just about at the halfway point of the year, it is just as good of a time as any to take stock of the data breach environment and start gathering lessons from others' missteps.

There's plenty to choose from. According to the Privacy Rights Clearinghouse, during the first half of 2012 we have seen 266 breaches that affect more than 18.5 million records. Dark Reading poured through the records and picked a breach for each month of 2012 so far to highlight as the most important exposures to learn from in the first half of the year.

[ Empower your users to stop big breaches. See When Will End Users Stop Being Fooled By Online Scams? ]

1. Zappos
Time Of Disclosure: January 2012

Records Breached: 24 million records, including names, email addresses, phone numbers, last four digits of credit card numbers, and encrypted passwords

Incident: A hacker gained access through a Zappos server into the company's internal network to snag personal information that could be used to phish Zappos customers.

Lessons Learned: While there may be no such thing as a good breach, many experts believe Zappos stands as a role model in reducing risk factors following a breach. For one, the encryption the company used for its passwords passed muster. Second, the company clearly had an incident response and notification plan in place and used it. In an era where it is not a question of if but when a breach will hit, these are two huge factors to consider.

2. University of North Carolina
Time Of Disclosure: February 2012

Records Breached: 350,000 records

Incident: Two separate incidents, one going back a decade, exposed Social Security numbers and financial information online.

Lessons Learned: System misconfigurations caused back-end university systems to be exposed on the Internet for public consumption. This is an increasingly familiar breach scenario these days, as organizations struggle to keep access control configurations in check so that database information is made available to the people who need it without being opened up to the world at large. Setting systems configurations is not sexy work, but it is critical.

3. Global Payment Systems
Time Of Disclosure: March 2012

Records Breached: 7 million consumer records, including 1.5 million credit cards

Incident: The credit card processor found in March that 1.5 million credit card records had been exported from its North American processing system. In its investigation, it most recently found that a database of new and past processing applicants had also been hit.

Lessons Learned: Without a doubt the most impactful breach of the year so far, this massive exposure offers a valuable lesson in the folly of point-in-time, check-box compliance. Hackers don't care whether your organization has been rubber-stamped by an auditor who sees the company is compliant on the day he or she signs the papers. Neither do regulatory bodies -- if you're breached, you're out of compliance. In the case of Global Payments, it has been delisted by the card companies as a company meeting its security standards until it can prove it is back in compliance.

4. South Carolina Health and Human Services
Time Of Disclosure: April 2012

Records Breached: 228,435 records

Incident: An employee was caught after emailing himself hundreds of thousands of patient records during the course of several months, including Medicaid ID numbers for more than 22,000 patients.

Lessons Learned: While many organizations are rightfully concerned about unauthorized access to their databases, sometimes it is the authorized users who can steal the most valuable and sensitive records. A data-centric security program that protects the information both inside and outside the database with means to track data movement is crucial to detecting insider theft before it does damage.

5. University of Nebraska
Time Of Disclosure: May 2012

Records Breached: 654,000 student records

Incident: Social Security numbers, addresses, grades, and more were stolen from the Nebraska Student Information System (NeSIS) database. Details of how the breach occurred are still under wraps, but a suspect has been identified and law enforcement is involved.

Lessons Learned: This particular breach affected a consolidated database system that stored volumes of information about students across the entire Nebraska State College System. As IT departments become more efficient and less siloed, information is increasingly consolidated into monolithic systems. This is a boon for organizations in many ways, but it also dramatically increases the importance of securing these data stores. Putting one's eggs in a single basket makes it prudent to make sure that basket is made out of Kevlar.

6. LinkedIn
Time Of Disclosure: June 2012

Records Breached: 6.5 million user passwords

Incident: The appearance of a password dump on an online forum prompted responses from the security community, which confirmed that the information was from LinkedIn. After some scrambling, LinkedIn confirmed the breach.

Lessons Learned: Just slapping any old encryption scheme onto sensitive data is not good enough these days. LinkedIn's failure to salt its passwords left them open to easy cracking by unauthorized parties. The incident also stands as an important lesson in incident response -- many experts believe LinkedIn was unprepared to swiftly handle response to a security incident such as this.

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