macOS High Sierra Vulnerability Allegedly Allows Malicious Third-Party Apps to Access Plaintext Keychain Data

macOS High Sierra, released to the public today, could be impacted by a major security flaw that could allow a hacker to steal the usernames and passwords of accounts stored in Keychain.

As it turns out, unsigned apps on macOS High Sierra (and potentially earlier versions of macOS) can allegedly access the Keychain info and display plaintext usernames and passwords without a user's master password.

Security researcher and ex-NSA analyst Patrick Wardle tweeted about the vulnerability early this morning and shared a video of the exploit in action.


For this vulnerability to work, a user needs to download malicious third-party code from an unknown source, something Apple actively discourages with warnings about apps downloaded outside of the Mac App Store or from non-trusted developers. In fact, Apple does not even allow apps from non-trusted developers to be downloaded without explicitly overriding security settings.

As demonstrated in the video above, Wardle created a proof-of-concept app called "keychainStealer" that was able to access plaintext passwords stored in Keychain for Twitter, Facebook, and Bank of America. Wardle spoke to Forbes about the vulnerability and said it's actually not hard to get malicious code running on a Mac even with Apple's protections in place.

"Without root priveleges, if the user is logged in, I can dump and exfiltrate the keychain, including plaintext passwords," Wardle told Forbes. "Normally you are not supposed to be able do that programmatically."

"Most attacks we see today involve social engineering and seem to be successful targeting Mac users," he added. "I'm not going to say the [keychain] exploit is elegant - but it does the job, doesn't require root and is 100% successful."

Wardle has not provided the full exploit code for malicious entities to take advantage of, and he believes Apple will patch the problem in a future update.

As Wardle has not released the full exploit code, it has not been double-checked by MacRumors or another source, so full details on the vulnerability are not known just yet.

Apple has not yet responded to requests for comment about the potential vulnerability.

Top Rated Comments

(View all)
Avatar
39 months ago
Would have been great if he contacted Apple before the OS was released. Just looking for attention. Jerk
Score: 58 Votes (Like | Disagree)
Avatar
39 months ago

Would have been great if he contacted Apple before the OS was released. Just looking for attention. Jerk

1. Would have been even greater if Apple had ppl who found these kind of bugs themselves before release.
2. You don't know if he found this yesterday. But sure hate on the guy who might have prevented your bank account password from ending up in the wrong hands.
Score: 52 Votes (Like | Disagree)
Avatar
39 months ago
On release day. That's embarrassing.
Score: 38 Votes (Like | Disagree)
Avatar
39 months ago
OMG, to enable this software you have to enter System Preferences, answer YES on two dialogues, and also enter your password. Then it may STEAL your not encoded things stored in the keychain (by default everything is stored encoded). I think I'm going to Windows now. This is just too much!!!

/irony ended
Score: 34 Votes (Like | Disagree)
Avatar
39 months ago
sigh. don't download junk, don't jeopardize your computer. Common sense is the best anti-virus.
Score: 21 Votes (Like | Disagree)
Avatar
39 months ago

If he did find it yesterday, he should have disclosed it to Apple and given them 90 days to fix it.

He doesn't owe Apple anything. Just like Apple doesn't owe him anything. He did them a favour.
Score: 19 Votes (Like | Disagree)

Top Stories

iOS 14 Widgets Offer iPhone Users Creative Home Screen Ideas

Sunday September 20, 2020 8:43 pm PDT by
Updated on September 22nd with hands on video. In iOS 14, Apple introduced ‌the concept of Home Screen‌ widgets, which provide information from apps at a glance. Widgets can be pinned to the Home Screen in various spots and sizes, allowing for many different layouts. Despite the relative lack of...

iPhone 12 Lineup Rumored to Be Named 'iPhone 12 mini,' 'iPhone 12,' 'iPhone 12 Pro,' and 'iPhone 12 Pro Max'

Monday September 21, 2020 5:24 am PDT by
Leaker known as "L0vetodream" has today shared the alleged naming for the upcoming iPhone 12 lineup on Twitter. The tweet proposes that the upcoming iPhone 12 models will be titled "iPhone 12 mini," "iPhone 12," "iPhone 12 Pro," and "iPhone 12 Pro Max." The names likely correspond to the three expected sizes of iPhone 12, with the 5.4-inch model being the iPhone 12 mini, the 6.7-inch model ...

PSA: New Apple Watch Owners Have to Return Entire Device for Ill-Fitting Solo Loop or Braided Solo Loop

Monday September 21, 2020 3:26 pm PDT by
With the Apple Watch Series 6, Apple introduced two new band options, the Solo Loop and the Braided Solo Loop. These new bands are unique because they have no clasps, buckles, or other fasteners, and instead use a stretch design to allow them to pull onto the wrist over the hand. Because these bands are not adjustable, Apple sells each one in nine different sizes to make sure each person...

Apple Releases First Public Betas of iOS 14.2 and iPadOS 14.2 With New Shazam Control Center Options

Monday September 21, 2020 10:34 am PDT by
Apple today seeded the first public betas of upcoming iOS 14.2 and iPadOS 14.2 updates to its public beta testing group, a few days after seeding the first betas to developers and a little less than a week after releasing the iOS 14 and iPadOS 14 updates. Public beta testers who have signed up for Apple's beta testing program can download the iOS and iPadOS‌ 14.2 updates over the air after ...

Kuo: Apple to Accelerate Adoption of Mini-LED Displays in iPad and Mac Notebook Lineups

Sunday September 20, 2020 10:00 pm PDT by
Increased competition among Apple's suppliers for mini-LED display chips will accelerate the company's adoption of the advanced technology in its iPad and MacBook lineups, according to a new research note from analyst Ming-Chi Kuo seen by MacRumors. Kuo says that while Epistar had been predicted to be the exclusive supplier of mini-LED chips for Apple products in 2021, Sanan Optoelectronics...

AirPods Studio Rumored to Come With U1 Chip, Ultra-Wideband Said to Be Vital to Future Apple Ecosystem

Sunday September 20, 2020 6:17 am PDT by
Proven leaker known as "L0vetodream" has today shared a range of information about the ultra-wideband U1 chip in Apple's upcoming AirTags item trackers and AirPods Studio headphones. The first of a series of tweets shared today simply stated that AirPods Studio will contain an ultra-wideband U1 chip. It seems likely that the U1 chip would be used in AirPods Studio to track the location of...

AT&T Already Working on 6G, Says 5G iPhones Might Not Be 'Massive Event' Due to Economic Uncertainty

Monday September 21, 2020 10:05 am PDT by
Apple's upcoming launch of 5G iPhones might not be a "massive event" due to economic uncertainty amid the global health crisis, AT&T Communications CEO Jeff McElfresh said in a paywalled interview published by CNBC. "I do believe that you will see many of the iPhone subscribers move to upgrade to the device," said McElfresh. "But I wouldn't forecast that it's going to be a massive event. I...

Microsoft Announces Outlook for Mac Redesign, Improvements to iOS and watchOS Apps

Tuesday September 22, 2020 8:56 am PDT by
Microsoft has today announced plans to bring a new design to its Outlook for Mac app along with several other improvements and features for Outlook on iOS and watchOS. In preparation for the public release of macOS Big Sur, Microsoft has been testing a new design for Outlook on Mac. The design includes Microsoft's Fluent icons and several design cues from Big Sur such as rounded corners....

iOS 14 Adoption Surpasses 25% Across iPhone and iPad Five Days After Release

Monday September 21, 2020 9:06 am PDT by
Five days after Apple released iOS 14, adoption of the software update has reached approximately 26 percent of active iPhone, iPad, and iPod touch devices, according to mobile analytics company Mixpanel. This includes iPadOS 14. iOS 14 adoption appears to be outpacing iOS 13, which was installed on approximately 20 percent of active devices one week after its release last year, according to...

When Will the iPhone 12 Launch? Here's What We Know

Wednesday September 16, 2020 6:12 am PDT by
Yesterday's "Time Flies" Apple event saw the release of the Apple Watch Series 6, Apple Watch SE, iPad 8, and iPad Air 4, but no new iPhone models. Rumors before the event strongly alleged that it would not see the unveiling of new iPhones, with many reports pointing to an October launch. The lack of new iPhone models yesterday seems to confirm that the iPhone 12 lineup will not appear...