Open Sourcing Zulip – a Dropbox Hack Week Project

This year’s Dropbox Hack Week saw some incredible projects take shape – from the talented team that visited Baltimore to research food deserts, to a project to recreate the fictional Pied Piper algorithm from HBO’s Silicon Valley. One of the most special elements of Hack Week, though, is that often times we’re able to share these exciting projects openly with our users and our community.

At Dropbox, we love and depend on numerous excellent open source projects, and we consider contributing back to the open source community to be vitally important. Popular open source projects that Dropbox has released include the zxcvbn password strength estimator,

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[CSP] Third Party Integrations and Privilege Separation

This is the fourth of four posts on our experience deploying Content Security Policy at Dropbox. If this sort of work interests you, we are hiring! We will also be at AppSec USA this week. Come say hi!

In previous blog posts, we discussed our experience deploying CSP at Dropbox, with a particular focus on the script-src directive that allows us to control script sources. With a locked down script-src whitelist, a nonce source, and mitigations to unsafe-eval, our CSP policy provided strong mitigations against XSS via injection attacks in our web application.

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[CSP] The Unexpected Eval

This is the third of four posts on our experience deploying Content Security Policy at Dropbox. If this sort of work interests you, we are hiring! We will also be at AppSec USA this week. Come say hi!

Previously, we discussed how at Dropbox we have deployed CSP at scale to protect against injection attacks. First, we discussed how we extract signal from violation reports to help create a host whitelist and restrict the sources of code running in our application. We also discussed how nonce sources allow us to mitigate XSS attacks due to content injections.

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[CSP] Unsafe-inline and nonce deployment

This is the second of four posts on our experience deploying Content Security Policy at Dropbox. If this sort of work interests you, we are hiring! We will also be at AppSec USA this week. Come say hi!

In the previous post, we discussed how to filter reports and deploy content source whitelists using CSP for the website. Typically, the most important content sources to whitelist are the source of your code, as defined by the script-src (and the object-src directive). A standard content-security-policy deployment will typically include a list of allowed domains like the main website and trusted CDNs in script-src as well as directives like 'unsafe-inline' and 'unsafe-eval'.

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[CSP] On Reporting and Filtering

This is the first of four posts on our experience deploying Content Security Policy at Dropbox. If this sort of work interests you, we are hiring! We will also be at AppSec USA this week. Come say hi!

At Dropbox, we are big fans of Content Security Policy or CSP. For those not familiar with the specification, I recommend reading Mike West’s excellent introduction to CSP. A quick recap: at its core, CSP is a declarative mechanism to whitelist content sources (such as sources for scripts,

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Dropbox Bug Bounty Program: Best Practices

Dropbox is recognizing security researchers for submitting security bugs through a bug bounty program with HackerOne and Bugcrowd. Whether you’re a security bug guru or a complete newbie, we want to make it as easy as possible to submit any bugs you find!

To this end, we’ve compiled the top 5 security bug report tips from our very own Security Engineers:

  1. Build a stronger report by including information on the actual and potential impact of the vulnerability, as well as details of how it could be exploited.
  2. Include the methodology you used to find the bug,

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