Terence Eden. He has a beard and is smiling.

Terence Eden’s Blog

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An open(ish) redirect on Mastodon

· 1 comment · 950 words · Viewed ~214 times

Cartoon of a tusked mastodon holding a phone.

I've responsibly disclosed a small security issue with Mastodon (GHSA-8982-p7pm-7mqw). It allows a sufficiently determined attacker to use any Mastodon instance to redirect unwary users to a malicious site. What do you think happens if you visit: https://mastodon.social/@PasswordReset/111285045683598517/admin? If you aren't logged in to that instance, it will redirect you to a 3rd party site.…

Responsible Disclosure: arXiv - redirect on login

· 1 comment · 350 words

A padlock engraved into a circuit board.

Suppose you are sent a link to a website - e.g. https://example.com/page/1234 But, before you can access it, you need to log in. So the website redirects you to: https://example.com/login?on_success=/page/1234 If you get the password right, you go to the original page you requested. Nice! But what happens if someone manipulates that query string? Suppose an adversary sends you a link like…

Responsible Disclosure: Abandoned Buckets and Billing Emails

· 1 comment · 450 words · Viewed ~403 times

Error saying the bucket does not exit.

A few weeks ago, I received a billing email from my phone provider O2. While glancing at it, I noticed all the images were broken. Viewing the source of the email showed that they were all coming from http:// mcsaatchi-email-preview.s3.amazonaws.com/o2/... What happens if we visit that domain? Ah, the dreaded "The specified bucket does not exist" error. At some point the images were…

Responsible Disclosure: XSS in Codeberg Pages

· 250 words · Viewed ~348 times

An XSS pop up alert on a webpage.

Codeberg is a hip new code hosting site - similar to GitHub and GitLab. And, much like Gits Hub & Lab, users can serve static content through Codeberg pages. Somehow I screwed up my configuration, and when I visited edent.codeberg.page/abc123 I got this error: Now, whenever I see something from the request echoed into the page's source, my hacker-sense starts tingling. What happens if I…