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Several Apple customers recently reported being targeted in elaborate phishing attacks that involve what appears to be a bug in Apple’s password reset feature. In this scenario, a target’s Apple devices are forced to display dozens of system-level prompts that prevent the devices from being used until the recipient responds “Allow” or “Don’t Allow” to each prompt. Assuming the user manages not to fat-finger the wrong button on the umpteenth password reset request, the scammers will then call the victim while spoofing Apple support in the caller ID, saying the user’s account is under attack and that Apple support needs to “verify” a one-time code.
Some of the many notifications Patel says he received from Apple all at once.
Parth Patel is an entrepreneur who is trying to build a startup in the conversational AI space. On March 23, Patel documented on Twitter/X a recent phishing campaign targeting him that involved what’s known as a “push bombing” or “MFA fatigue” attack, wherein the phishers abuse a feature or weakness of a multi-factor authentication (MFA) system in a way that inundates the target’s device(s) with alerts to approve a password change or login.
“All of my devices started blowing up, my watch, laptop and phone,” Patel told KrebsOnSecurity. “It was like this system notification from Apple to approve [a reset of the account password], but I couldn’t do anything else with my phone. I had to go through and decline like 100-plus notifications.”
Some people confronted with such a deluge may eventually click “Allow” to the incessant password reset prompts — just so they can use their phone again. Others may inadvertently approve one of these prompts, which will also appear on a user’s Apple watch if they have one.
But the attackers in this campaign had an ace up their sleeves: Patel said after denying all of the password reset prompts from Apple, he received a call on his iPhone that said it was from Apple Support (the number displayed was 1-800-275-2273, Apple’s real customer support line).
“I pick up the phone and I’m super suspicious,” Patel recalled. “So I ask them if they can verify some information about me, and after hearing some aggressive typing on his end he gives me all this information about me and it’s totally accurate.”
All of it, that is, except his real name. Patel said when he asked the fake Apple support rep to validate the name they had on file for the Apple account, the caller gave a name that was not his but rather one that Patel has only seen in background reports about him that are for sale at a people-search website called PeopleDataLabs.
Patel said he has worked fairly hard to remove his information from multiple people-search websites, and he found PeopleDataLabs uniquely and consistently listed this inaccurate name as an alias on his consumer profile.
“For some reason, PeopleDataLabs has three profiles that come up when you search for my info, and two of them are mine but one is an elementary school teacher from the midwest,” Patel said. “I asked them to verify my name and they said Anthony.”
Patel said the goal of the voice phishers is to trigger an Apple ID reset code to be sent to the user’s device, which is a text message that includes a one-time password. If the user supplies that one-time code, the attackers can then reset the password on the account and lock the user out. They can also then remotely wipe all of the user’s Apple devices.
Chris is a cryptocurrency hedge fund owner who asked that only his first name be used so as not to paint a bigger target on himself. Chris told KrebsOnSecurity he experienced a remarkably similar phishing attempt in late February.
“The first alert I got I hit ‘Don’t Allow’, but then right after that I got like 30 more notifications in a row,” Chris said. “I figured maybe I sat on my phone weird, or was accidentally pushing some button that was causing these, and so I just denied them all.”
Chris says the attackers persisted hitting his devices with the reset notifications for several days after that, and at one point he received a call on his iPhone that said it was from Apple support.
“I said I would call them back and hung up,” Chris said, demonstrating the proper response to such unbidden solicitations. “When I called back to the real Apple, they couldn’t say whether anyone had been in a support call with me just then. They just said Apple states very clearly that it will never initiate outbound calls to customers — unless the customer requests to be contacted.”
Massively freaking out that someone was trying to hijack his digital life, Chris said he changed his passwords and then went to an Apple store and bought a new iPhone. From there, he created a new Apple iCloud account using a brand new email address.
Chris said he then proceeded to get even more system alerts on his new iPhone and iCloud account — all the while still sitting at the local Apple Genius Bar.
Chris told KrebsOnSecurity his Genius Bar tech was mystified about the source of the alerts, but Chris said he suspects that whatever the phishers are abusing to rapidly generate these Apple system alerts requires knowing the phone number on file for the target’s Apple account. After all, that was the only aspect of Chris’s new iPhone and iCloud account that hadn’t changed.
“Ken” is a security industry veteran who spoke on condition of anonymity. Ken said he first began receiving these unsolicited system alerts on his Apple devices earlier this year, but that he has not received any phony Apple support calls as others have reported.
“This recently happened to me in the middle of the night at 12:30 a.m.,” Ken said. “And even though I have my Apple watch set to remain quiet during the time I’m usually sleeping at night, it woke me up with one of these alerts. Thank god I didn’t press ‘Allow,’ which was the first option shown on my watch. I had to scroll watch the wheel to see and press the ‘Don’t Allow’ button.”
Ken shared this photo he took of an alert on his watch that woke him up at 12:30 a.m. Ken said he had to scroll on the watch face to see the “Don’t Allow” button.
Ken didn’t know it when all this was happening (and it’s not at all obvious from the Apple prompts), but clicking “Allow” would not have allowed the attackers to change Ken’s password. Rather, clicking “Allow” displays a six digit PIN that must be entered on Ken’s device — allowing Ken to change his password. It appears that these rapid password reset prompts are being used to make a subsequent inbound phone call spoofing Apple more believable.
Ken said he contacted the real Apple support and was eventually escalated to a senior Apple engineer. The engineer assured Ken that turning on an Apple Recovery Key for his account would stop the notifications once and for all.
A recovery key is an optional security feature that Apple says “helps improve the security of your Apple ID account.” It is a randomly generated 28-character code, and when you enable a recovery key it is supposed to disable Apple’s standard account recovery process. The thing is, enabling it is not a simple process, and if you ever lose that code in addition to all of your Apple devices you will be permanently locked out.
Ken said he enabled a recovery key for his account as instructed, but that it hasn’t stopped the unbidden system alerts from appearing on all of his devices every few days.
KrebsOnSecurity tested Ken’s experience, and can confirm that enabling a recovery key does nothing to stop a password reset prompt from being sent to associated Apple devices. Visiting Apple’s “forgot password” page — https://iforgot.apple.com — asks for an email address and for the visitor to solve a CAPTCHA.
After that, the page will display the last two digits of the phone number tied to the Apple account. Filling in the missing digits and hitting submit on that form will send a system alert, whether or not the user has enabled an Apple Recovery Key.
The password reset page at iforgot.apple.com.
What sanely designed authentication system would send dozens of requests for a password change in the span of a few moments, when the first requests haven’t even been acted on by the user? Could this be the result of a bug in Apple’s systems?
Apple has not yet responded to requests for comment.
Throughout 2022, a criminal hacking group known as LAPSUS$ used MFA bombing to great effect in intrusions at Cisco, Microsoft and Uber. In response, Microsoft began enforcing “MFA number matching,” a feature that displays a series of numbers to a user attempting to log in with their credentials. These numbers must then be entered into the account owner’s Microsoft authenticator app on their mobile device to verify they are logging into the account.
Kishan Bagaria is a hobbyist security researcher and engineer who founded the website texts.com (now owned by Automattic), and he’s convinced Apple has a problem on its end. In August 2019, Bagaria reported to Apple a bug that allowed an exploit he dubbed “AirDoS” because it could be used to let an attacker infinitely spam all nearby iOS devices with a system-level prompt to share a file via AirDrop — a file-sharing capability built into Apple products.
Apple fixed that bug nearly four months later in December 2019, thanking Bagaria in the associated security bulletin. Bagaria said Apple’s fix was to add stricter rate limiting on AirDrop requests, and he suspects that someone has figured out a way to bypass Apple’s rate limit on how many of these password reset requests can be sent in a given timeframe.
“I think this could be a legit Apple rate limit bug that should be reported,” Bagaria said.
Apple seems requires a phone number to be on file for your account, but after you’ve set up the account it doesn’t have to be a mobile phone number. KrebsOnSecurity’s testing shows Apple will accept a VOIP number (like Google Voice). So, changing your account phone number to a VOIP number that isn’t widely known would be one mitigation here.
One caveat with the VOIP number idea: Unless you include a real mobile number, Apple’s iMessage and Facetime applications will be disabled for that device. This might a bonus for those concerned about reducing the overall attack surface of their Apple devices, since zero-click zero-days in these applications have repeatedly been used by spyware purveyors.
Also, it appears Apple’s password reset system will accept and respect email aliases. Adding a “+” character after the username portion of your email address — followed by a notation specific to the site you’re signing up at — lets you create an infinite number of unique email addresses tied to the same account.
For instance, if I were signing up at example.com, I might give my email address as krebsonsecurity+example@gmail.com. Then, I simply go back to my inbox and create a corresponding folder called “Example,” along with a new filter that sends any email addressed to that alias to the Example folder. In this case, however, perhaps a less obvious alias than “+apple” would be advisable.
Update, March 27, 5:06 p.m. ET: Added perspective on Ken’s experience. Also included a What Can You Do? section.
Microsoft today issued security updates for more than 100 newly-discovered vulnerabilities in its Windows operating system and related software, including four flaws that are already being exploited. In addition, Apple recently released emergency updates to quash a pair of zero-day bugs in iOS.
Apple last week shipped emergency updates in iOS 17.0.3 and iPadOS 17.0.3 in response to active attacks. The patch fixes CVE-2023-42724, which attackers have been using in targeted attacks to elevate their access on a local device.
Apple said it also patched CVE-2023-5217, which is not listed as a zero-day bug. However, as Bleeping Computer pointed out, this flaw is caused by a weakness in the open-source “libvpx” video codec library, which was previously patched as a zero-day flaw by Google in the Chrome browser and by Microsoft in Edge, Teams, and Skype products. For anyone keeping count, this is the 17th zero-day flaw that Apple has patched so far this year.
Fortunately, the zero-days affecting Microsoft customers this month are somewhat less severe than usual, with the exception of CVE-2023-44487. This weakness is not specific to Windows but instead exists within the HTTP/2 protocol used by the World Wide Web: Attackers have figured out how to use a feature of HTTP/2 to massively increase the size of distributed denial-of-service (DDoS) attacks, and these monster attacks reportedly have been going on for several weeks now.
Amazon, Cloudflare and Google all released advisories today about how they’re addressing CVE-2023-44487 in their cloud environments. Google’s Damian Menscher wrote on Twitter/X that the exploit — dubbed a “rapid reset attack” — works by sending a request and then immediately cancelling it (a feature of HTTP/2). “This lets attackers skip waiting for responses, resulting in a more efficient attack,” Menscher explained.
Natalie Silva, lead security engineer at Immersive Labs, said this flaw’s impact to enterprise customers could be significant, and lead to prolonged downtime.
“It is crucial for organizations to apply the latest patches and updates from their web server vendors to mitigate this vulnerability and protect against such attacks,” Silva said. In this month’s Patch Tuesday release by Microsoft, they have released both an update to this vulnerability, as well as a temporary workaround should you not be able to patch immediately.”
Microsoft also patched zero-day bugs in Skype for Business (CVE-2023-41763) and Wordpad (CVE-2023-36563). The latter vulnerability could expose NTLM hashes, which are used for authentication in Windows environments.
“It may or may not be a coincidence that Microsoft announced last month that WordPad is no longer being updated, and will be removed in a future version of Windows, although no specific timeline has yet been given,” said Adam Barnett, lead software engineer at Rapid7. “Unsurprisingly, Microsoft recommends Word as a replacement for WordPad.”
Other notable bugs addressed by Microsoft include CVE-2023-35349, a remote code execution weakness in the Message Queuing (MSMQ) service, a technology that allows applications across multiple servers or hosts to communicate with each other. This vulnerability has earned a CVSS severity score of 9.8 (10 is the worst possible). Happily, the MSMQ service is not enabled by default in Windows, although Immersive Labs notes that Microsoft Exchange Server can enable this service during installation.
Speaking of Exchange, Microsoft also patched CVE-2023-36778, a vulnerability in all current versions of Exchange Server that could allow attackers to run code of their choosing. Rapid7’s Barnett said successful exploitation requires that the attacker be on the same network as the Exchange Server host, and use valid credentials for an Exchange user in a PowerShell session.
For a more detailed breakdown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.
Microsoft today issued software updates to fix at least five dozen security holes in Windows and supported software, including patches for two zero-day vulnerabilities that are already being exploited. Also, Adobe, Google Chrome and Apple iOS users may have their own zero-day patching to do.
On Sept. 7, researchers at Citizen Lab warned they were seeing active exploitation of a “zero-click,” zero-day flaw to install spyware on iOS devices without any interaction from the victim.
“The exploit chain was capable of compromising iPhones running the latest version of iOS (16.6) without any interaction from the victim,” the researchers wrote.
According to Citizen Lab, the exploit uses malicious images sent via iMessage, an embedded component of Apple’s iOS that has been the source of previous zero-click flaws in iPhones and iPads.
Apple says the iOS flaw (CVE-2023-41064) does not seem to work against devices that have its ultra-paranoid “Lockdown Mode” enabled. This feature restricts non-essential iOS features to reduce the device’s overall attack surface, and it was designed for users concerned that they may be subject to targeted attacks. Citizen Lab says the bug it discovered was being exploited to install spyware made by the Israeli cyber surveillance company NSO Group.
This vulnerability is fixed in iOS 16.6.1 and iPadOS 16.6.1. To turn on Lockdown Mode in iOS 16, go to Settings, then Privacy and Security, then Lockdown Mode.
Not to be left out of the zero-day fun, Google acknowledged on Sept. 11 that an exploit for a heap overflow bug in Chrome is being exploited in the wild. Google says it is releasing updates to fix the flaw, and that restarting Chrome is the way to apply any pending updates. Interestingly, Google says this bug was reported by Apple and Citizen Lab.
On the Microsoft front, a zero-day in Microsoft Word is among the more concerning bugs fixed today. Tracked as CVE-2023-36761, it is flagged as an “information disclosure” vulnerability. But that description hardly grasps at the sensitivity of the information potentially exposed here.
Tom Bowyer, manager of product security at Automox, said exploiting this vulnerability could lead to the disclosure of Net-NTLMv2 hashes, which are used for authentication in Windows environments.
“If a malicious actor gains access to these hashes, they can potentially impersonate the user, gaining unauthorized access to sensitive data and systems,” Bowyer said, noting that CVE-2023-36761 can be exploited just by viewing a malicious document in the Windows preview pane. “They could also conduct pass-the-hash attacks, where the attacker uses the hashed version of a password to authenticate themselves without needing to decrypt it.”
The other Windows zero-day fixed this month is CVE-2023-36802. This is an “elevation of privilege” flaw in the “Microsoft Streaming Service Proxy,” which is built into Windows 10, 11 and Windows Server versions. Microsoft says an attacker who successfully exploits the bug can gain SYSTEM level privileges on a Windows computer.
Five of the flaws Microsoft fixed this month earned its “critical” rating, which the software giant reserves for vulnerabilities that can be exploited by malware or malcontents with little or no interaction by Windows users.
According to the SANS Internet Storm Center, the most serious critical bug in September’s Patch Tuesday is CVE-2023-38148, which is a weakness in the Internet Connection Sharing service on Windows. Microsoft says an unauthenticated attacker could leverage the flaw to install malware just sending a specially crafted data packet to a vulnerable Windows system.
Finally, Adobe has released critical security updates for its Adobe Reader and Acrobat software that also fixes a zero-day vulnerability (CVE-2023-26369). More details are at Adobe’s advisory.
For a more granular breakdown of the Windows updates pushed out today, check out Microsoft Patch Tuesday by Morphus Labs. In the meantime, consider backing up your data before updating Windows, and keep an eye on AskWoody.com for reports of any widespread problems with any of the updates released as part of September’s Patch Tuesday.
Update: Mozilla also has fixed zero-day flaw in Firefox and Thunderbird, and the Brave browser was updated as well. It appears the common theme here is any software that uses a code library called “libwebp,” and that this vulnerability is being tracked as CVE-2023-4863.
“This includes Electron-based applications, for example – Signal,” writes StackDiary.com. “Electron patched the vulnerability yesterday. Also, software like Honeyview (from Bandisoft) released an update to fix the issue. CVE-2023-4863 was falsely marked as Chrome-only by Mitre and other organizations that track CVE’s and 100% of media reported this issue as “Chrome only”, when it’s not.”
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