‘Tis the season when even those who know a thing or two about Internet scams tend to let down their guard in the face of an eye-popping discount or the stress of last-minute holiday shopping. So here’s a quick refresher course on how to make it through the next few weeks without getting snookered online.

U.S. Postal Service just fixed a security weakness that allowed anyone who has an account at usps.com to view account details for some 60 million other users, and in some cases to modify account details on their behalf.

KrebsOnSecurity was contacted last week by a researcher who discovered the problem, but who asked to remain anonymous. The researcher said he informed the USPS about his finding more than a year ago yet never received a response. After confirming his findings, this author contacted the USPS, which promptly addressed the issue.

A California man who pleaded guilty Tuesday to causing dozens of swatting attacks — including a deadly incident in Kansas last year — now faces 20 or more years in prison.

Microsoft on Tuesday released 16 software updates to fix more than 60 security holes in various flavors of Windows and other Microsoft products. Adobe’s also got security patches available for Flash, Acrobat and Adobe Reader users. 

If you own a domain name that gets decent traffic and you fail to pay its annual renewal fee, chances are this mistake will be costly for you and for others. Lately, neglected domains have been getting scooped up by crooks who use them to set up fake e-commerce sites that steal credit card details from unwary shoppers.

A Connecticut man who’s earned “bug bounty” rewards and public recognition from top telecom companies for finding and reporting security holes in their Web sites secretly operated a service that leveraged these same flaws to sell their customers’ personal data, KrebsOnSecurity has learned.

A year ago, KrebsOnSecurity warned that “Informed Delivery,” a new offering from the U.S. Postal Service (USPS) that lets residents view scanned images of all incoming mail, was likely to be abused by identity thieves and other fraudsters unless the USPS beefed up security around the program and made it easier for people to opt out. This week, the U.S. Secret Service issued an internal alert warning that many of its field offices have reported crooks are indeed using Informed Delivery to commit various identity theft and credit card fraud schemes.

KrebsOnSecurity recently had a chance to interview members of the REACT Task Force, a team of law enforcement officers and prosecutors based in Santa Clara, Calif. that has been tracking down individuals engaged in unauthorized “SIM swaps” — a complex form of mobile phone fraud that is often used to steal large amounts of cryptocurrencies and other items of value from victims. Snippets from that fascinating conversation are recounted below, and punctuated by accounts from a recent victim who lost more than $100,000 after his mobile phone number was hijacked.

Crooks who hack online merchants to steal payment card data are constantly coming up with crafty ways to hide their malicious code on Web sites. In Internet ages past, this often meant obfuscating it as giant blobs of gibberish text that is obvious even to the untrained eye. These days, a compromised e-commerce site is more likely to be seeded with a tiny snippet of code that invokes a hostile domain which appears harmless or that is virtually indistinguishable from the hacked site’s own domain.

Thieves are combining SMS-based phishing attacks with new “cardless” ATMs to rapidly convert phished bank account credentials into cash. Recent arrests in Ohio shed light on how this scam works.