Thursday, May 14, 2020 [Tweets] [Favorites]

Security Flaws in Adobe Acrobat Reader

Yuebin Sun (tweet, MacRumors):

Today, Adobe Acrobat Reader DC for macOS patched three critical vulnerabilities […] I reported. The only requirement needed to trigger the vulnerabilities is that Adobe Acrobat Reader DC has been installed. A normal user on macOS(with SIP enabled) can locally exploit this vulnerabilities chain to elevate privilege to the ROOT without a user being aware.

[…]

SMJobBlessHelper is based on NSXPC, its client checking exists in [SMJobBlessHelper listener:shouldAcceptNewConnection:]. The checking logic is as pseudo-code shows below, gets the client’s PID, and then obtains Bundle ID based on the client’s process path, the client will be trusted if its Bundle ID is “com.adobe.ARMDC”.

[…]

Yes, the symlink is still valid, it can help us to bypass temp directory protection. I can force /var/folders/zz/xxxxx/T/download/ARMDCHammer to link to anywhere.

[…]

So if we can replace the “/tmp/test/hello_root” with our malicious file after validateBinary, launchARMHammer will launch our malicious process.

You may think the race condition window is too narrow to control, I will show the tricks later.

I don’t like it when third-party code uses the name of a system class or function as a prefix.

Previously:

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