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Hacker Finds Bug to Edit or Delete Any Medium Post (vice.com)
Joseph Cox, reporting for Motherboard: Medium has become the go-to home for extended blog posts from researchers, CEOs, and even the President of the United States. Now, one hacker has found a way to edit or delete any post on the publishing platform. "I tried to think of different possibilities or testing cases on how can I delete a story of any user. And fortunately, I found a severe bug," Philippines-based freelance penetration test and bug bounty hunter Allan Jay Dumanhug told Motherboard in an email. The trick, Dumanhug explained in a blog post published at the end of last month, centres around Medium's "Publications" feature. Users can create their own publications -- perhaps a page dedicated to infosec news, for example -- and then request to add other users' posts to it. Each post on Medium is given its own unique, 12-character identifier code. The person who authored the post has to approve that request, otherwise their story doesn't go anywhere. But Dumanhug found that while adding his own story to his own publication, he could intercept the HTTP request and simply change the identifier to that of another post.
First clue was the puffery in the lede.
clearly the name Medium refers to their level of security.
For a moment there, I thought he'd found a way to delete a post from any medium. That would have been a whole lot worse.
If a white-hat hacker had found this exploit, he would've gone ahead and deleted all Medium posts. And there would have been much rejoicing.
According to netcraft, more people are aware medium exists than are aware slashdot [still] exists.
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Any real mediums would see the deletion coming....
That's not a bug. It's just a total lack of authentication. No put in the effort, because no one cared. Congrats. This ain't a surprise.
Perhaps a blogging platform needn't the same level of security as a bank or nuclear power centre.
A lesson for young programmers: if you're going to divulge your UIDs (or make them easily guessable, like sequential), be sure to pair them with a random string before you accept them from an outside source -- like user input.
"he could intercept the HTTP request and simply change the identifier to that of another post."
Stand back guys, we got a pro here.
It's a rare Medium that's done well.
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
Rule 1. Never trust any user input.
Rule 2. Using encrypted checksums and other input checking to verify the contents of system generated forms before accepting them is a good thing.
"GET / HTTP/1.0" 200 51230 "-" "Mozilla/4.0 (compatible; Setec Astronomy)"
Good! Let's hope it will stay that way.
Ezekiel 23:20
So far I've been fairly pleased with reading things on Medium, although some of the weird sliding underlay pics I can do without. So when will the nice experience give way to a horrible one? When they force ads on those who run ad blockers? When they decide they aren't making enough money from the site as is? Micro transactions? So far it's been almost too good to be true.... which makes me deeply suspicious.
It's a different model. They make money using native advertising.
"Somebody has to do something. It's just incredibly pathetic it has to be us."
--- Jerry Garcia