ZIP is a great format—it’s extremely broadly deployed, relatively simple, and supports a wide variety of use-cases pretty well. ZIP is the underlying format beneath Java (.jar) Archives, Office (docx/xlsx/pptx) files, Fiddler (.saz) Session Archive ZIP files, and many more. Even though some features (Unicode filenames, AES encryption, advanced compression engines) aren’t supported by allContinue reading “Compression Context”
Tag Archives: security
Downloads and the Mark-of-the-Web
Last update: October 28, 2025 Background To help protect the user and their device, Windows and its applications will often treat files originating from the Internet more cautiously than files generated locally. The Windows Security Zones determination process is most directly implemented by the MapURLToZone API; that API accepts a URL or a file pathContinue reading “Downloads and the Mark-of-the-Web”
Seek and Destroy Non-Secure References Using the moarTLS Analyzer
tl;dr: I made a Chrome Extension that finds security vulnerabilities.It’s now available for Firefox too! To secure web connections, TLS-enabling servers is only half the battle; the other half is ensuring that TLS is used everywhere. Unfortunately, many HTTPS sites today include insecure references that provide an network-based attacker the opportunity to break into theContinue reading “Seek and Destroy Non-Secure References Using the moarTLS Analyzer”
Web Developers and Footguns
If you offer web developers footguns, you’d better staff up your local trauma department. In a prior life, I wrote a lot about Same-Origin-Policy, including the basic DENY-READ principle that means that script running in the context of origin A.com cannot read content from B.com. When we built the (ill-fated) XDomainRequest object in IE8, weContinue reading “Web Developers and Footguns”
Extended Validation Certificates – The Introduction
In 2005, one of my first projects on the Internet Explorer team was improving the user-experience for HTTPS sites (“SSLUX”). Our first task was to change the certificate error experience from the confusing and misleading modal dialog box: … to something that more clearly conveyed the risk and which more clearly discouraged users from acceptingContinue reading “Extended Validation Certificates – The Introduction”
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