Researcher Uses macOS App Screenshot Feature to Steal Passwords, Tokens, Keys

[LASER_oneXM]

Malicious app developers can secretly abuse a macOS API function to take screenshots of the user's screen and then use OCR (Optical Character Recognition) to programmatically read the text found in the image.

The function is CGWindowListCreateImage, often utilized by Mac apps that take screenshots or live stream a user's desktop.

API function can be abused to read sensitive user data
According to Fastlane Tools founder Felix Krause, any Mac app, sandboxed or not, can access this function and secretly take screenshots of the user's screen.

Krause argues that miscreants can abuse this privacy loophole and utilize CGWindowListCreateImage to take screenshots of the screen without the user's permission.

In experiments he carried out, Krause says he was able to use an OCR library to read various types of information captured using CGWindowListCreateImage. He argues that an attacker can:

⌔ Read passwords and keys from password managers
⌔ Read sensitive source code, API keys, or similar data
⌔ Read emails and messages users open on their Mac
⌔ Detect what web services users employ (e.g. email providers, password manager, app lists, etc.)
⌔ Learn personal information about the user, like their bank details, salary, address, etc.

The researcher filed a bug with Apple yesterday, letting the company know of the issue he found. Krause also went public with his findings on his blog, which is a strange move as most researchers give companies time to fix reported issues. It may be that the feature has already been abused for such attacks. Bleeping Computer has reached out to the researcher for comment on his motives.

 

[Sunshine-boy]

What about The windows? who knows how many undiscovered methods Exist?Better to don't install or run anything

 

[Deleted member 65228]

What about The windows? who knows how many undiscovered methods Exist?Better to don't install or run anything

Well, if your system is compromised then an attacker can record the screen and this could potentially leak sensitive data, including but not limited to login credentials. Behaviour like this isn't specific to Mac OS X.