Adobe and Microsoft each released updates today to tackle critical security weaknesses in their software. Microsoft’s December patch batch is relatively light, addressing more than three dozen vulnerabilities in Windows and related applications. Adobe has issued security fixes for its Acrobat and PDF Reader products, and has a patch for yet another zero-day flaw in Flash Player that is already being exploited in the wild.

Back in April 2015, I tweeted about receiving a letter via snail mail suggesting the search engine rankings for a domain registered in my name would suffer if I didn’t pay a bill for some kind of dubious-looking service I’d never heard of. But it wasn’t until the past week that it become clear how many organizations — including towns, cities and political campaigns — actually have fallen for this brazen scam.

The alleged ringleader of a gang of cyber hooligans that made bomb threats against hundreds of schools and launched debilitating denial-of-service attacks against Web sites (including KrebsOnSecurity on multiple occasions) has been sentenced to three years in a U.K. prison, and faces the possibility of additional charges from U.S.-based law enforcement officials. 

Software giant Citrix Systems recently forced a password reset for many users of its Sharefile content collaboration service, warning it would be doing this on a regular basis in response to password-guessing attacks that target people who re-use passwords across multiple Web sites. Many Sharefile users interpreted this as a breach at Citrix and/or Sharefile, but the company maintains that’s not the case. Here’s a closer look at what happened, and some ideas about how to avoid a repeat of this scenario going forward.

The parent firm of bling retailers Jared and Kay Jewelers has fixed a bug in the Web sites of both companies that exposed the order information for all of their online customers.

We don’t yet know the root cause(s) that forced Marriott this week to disclose a four-year-long breach involving the personal and financial information of 500 million guests of its Starwood hotel properties. But anytime we see such a colossal intrusion go undetected for so long, the ultimate cause is usually a failure to adopt the most important principle in cybersecurity defense that applies to both corporations and consumers: Assume you are compromised.

Hospitality giant Marriott today disclosed a massive data breach exposing the personal and financial information on as many as a half billion customers who made reservations at any of its Starwood properties over the past four years.

Maybe you were once advised to “look for the padlock” as a means of telling legitimate e-commerce sites from phishing or malware traps. Unfortunately, this has never been more useless advice. New research indicates that half of all phishing scams are now hosted on Web sites whose Internet address includes the padlock and begins with “https://”.

‘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.