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Microsoft today released updates to fix more than 60 security holes in Windows computers and supported software, including two “zero-day” vulnerabilities in Windows that are already being exploited in active attacks. There are also important security patches available for macOS and Adobe users, and for the Chrome Web browser, which just patched its own zero-day flaw.
First, the zero-days. CVE-2024-30051 is an “elevation of privilege” bug in a core Windows library. Satnam Narang at Tenable said this flaw is being used as part of post-compromise activity to elevate privileges as a local attacker.
“CVE-2024-30051 is used to gain initial access into a target environment and requires the use of social engineering tactics via email, social media or instant messaging to convince a target to open a specially crafted document file,” Narang said. “Once exploited, the attacker can bypass OLE mitigations in Microsoft 365 and Microsoft Office, which are security features designed to protect end users from malicious files.”
Kaspersky Lab, one of two companies credited with reporting exploitation of CVE-2024-30051 to Microsoft, has published a fascinating writeup on how they discovered the exploit in a file shared with Virustotal.com.
Kaspersky said it has since seen the exploit used together with QakBot and other malware. Emerging in 2007 as a banking trojan, QakBot (a.k.a. Qbot and Pinkslipbot) has morphed into an advanced malware strain now used by multiple cybercriminal groups to prepare newly compromised networks for ransomware infestations.
CVE-2024-30040 is a security feature bypass in MSHTML, a component that is deeply tied to the default Web browser on Windows systems. Microsoft’s advisory on this flaw is fairly sparse, but Kevin Breen from Immersive Labs said this vulnerability also affects Office 365 and Microsoft Office applications.
“Very little information is provided and the short description is painfully obtuse,” Breen said of Microsoft’s advisory on CVE-2024-30040.
The only vulnerability fixed this month that earned Microsoft’s most-dire “critical” rating is CVE-2024-30044, a flaw in Sharepoint that Microsoft said is likely to be exploited. Tenable’s Narang notes that exploitation of this bug requires an attacker to be authenticated to a vulnerable SharePoint Server with Site Owner permissions (or higher) first and to take additional steps in order to exploit this flaw, which makes this flaw less likely to be widely exploited as most attackers follow the path of least resistance.
Five days ago, Google released a security update for Chrome that fixes a zero-day in the popular browser. Chrome usually auto-downloads any available updates, but it still may require a complete restart of the browser to install them. If you use Chrome and see a “Relaunch to update” message in the upper right corner of the browser, it’s time to restart.
Apple has just shipped macOS Sonoma 14.5 update, which includes nearly two dozen security patches. To ensure your Mac is up-to-date, go to System Settings, General tab, then Software Update and follow any prompts.
Finally, Adobe has critical security patches available for a range of products, including Acrobat, Reader, Illustrator, Adobe Substance 3D Painter, Adobe Aero, Adobe Animate and Adobe Framemaker.
Regardless of whether you use a Mac or Windows system (or something else), it’s always a good idea to backup your data and or system before applying any security updates. For a closer look at the individual fixes released by Microsoft today, check out the complete list over at the SANS Internet Storm Center. Anyone in charge of maintaining Windows systems in an enterprise environment should keep an eye on askwoody.com, which usually has the scoop on any wonky Windows patches.
Update, May 15, 8:28 a.m.: Corrected misattribution of CVE-2024-30051.
Virtual private networking (VPN) companies market their services as a way to prevent anyone from snooping on your Internet usage. But new research suggests this is a dangerous assumption when connecting to a VPN via an untrusted network, because attackers on the same network could force a target’s traffic off of the protection provided by their VPN without triggering any alerts to the user.
Image: Shutterstock.
When a device initially tries to connect to a network, it broadcasts a message to the entire local network stating that it is requesting an Internet address. Normally, the only system on the network that notices this request and replies is the router responsible for managing the network to which the user is trying to connect.
The machine on a network responsible for fielding these requests is called a Dynamic Host Configuration Protocol (DHCP) server, which will issue time-based leases for IP addresses. The DHCP server also takes care of setting a specific local address — known as an Internet gateway — that all connecting systems will use as a primary route to the Web.
VPNs work by creating a virtual network interface that serves as an encrypted tunnel for communications. But researchers at Leviathan Security say they’ve discovered it’s possible to abuse an obscure feature built into the DHCP standard so that other users on the local network are forced to connect to a rogue DHCP server.
“Our technique is to run a DHCP server on the same network as a targeted VPN user and to also set our DHCP configuration to use itself as a gateway,” Leviathan researchers Lizzie Moratti and Dani Cronce wrote. “When the traffic hits our gateway, we use traffic forwarding rules on the DHCP server to pass traffic through to a legitimate gateway while we snoop on it.”
The feature being abused here is known as DHCP option 121, and it allows a DHCP server to set a route on the VPN user’s system that is more specific than those used by most VPNs. Abusing this option, Leviathan found, effectively gives an attacker on the local network the ability to set up routing rules that have a higher priority than the routes for the virtual network interface that the target’s VPN creates.
“Pushing a route also means that the network traffic will be sent over the same interface as the DHCP server instead of the virtual network interface,” the Leviathan researchers said. “This is intended functionality that isn’t clearly stated in the RFC [standard]. Therefore, for the routes we push, it is never encrypted by the VPN’s virtual interface but instead transmitted by the network interface that is talking to the DHCP server. As an attacker, we can select which IP addresses go over the tunnel and which addresses go over the network interface talking to our DHCP server.”
Leviathan found they could force VPNs on the local network that already had a connection to arbitrarily request a new one. In this well-documented tactic, known as a DHCP starvation attack, an attacker floods the DHCP server with requests that consume all available IP addresses that can be allocated. Once the network’s legitimate DHCP server is completely tied up, the attacker can then have their rogue DHCP server respond to all pending requests.
“This technique can also be used against an already established VPN connection once the VPN user’s host needs to renew a lease from our DHCP server,” the researchers wrote. “We can artificially create that scenario by setting a short lease time in the DHCP lease, so the user updates their routing table more frequently. In addition, the VPN control channel is still intact because it already uses the physical interface for its communication. In our testing, the VPN always continued to report as connected, and the kill switch was never engaged to drop our VPN connection.”
The researchers say their methods could be used by an attacker who compromises a DHCP server or wireless access point, or by a rogue network administrator who owns the infrastructure themselves and maliciously configures it. Alternatively, an attacker could set up an “evil twin” wireless hotspot that mimics the signal broadcast by a legitimate provider.
Bill Woodcock is executive director at Packet Clearing House, a nonprofit based in San Francisco. Woodcock said Option 121 has been included in the DHCP standard since 2002, which means the attack described by Leviathan has technically been possible for the last 22 years.
“They’re realizing now that this can be used to circumvent a VPN in a way that’s really problematic, and they’re right,” Woodcock said.
Woodcock said anyone who might be a target of spear phishing attacks should be very concerned about using VPNs on an untrusted network.
“Anyone who is in a position of authority or maybe even someone who is just a high net worth individual, those are all very reasonable targets of this attack,” he said. “If I were trying to do an attack against someone at a relatively high security company and I knew where they typically get their coffee or sandwich at twice a week, this is a very effective tool in that toolbox. I’d be a little surprised if it wasn’t already being exploited in that way, because again this isn’t rocket science. It’s just thinking a little outside the box.”
Successfully executing this attack on a network likely would not allow an attacker to see all of a target’s traffic or browsing activity. That’s because for the vast majority of the websites visited by the target, the content is encrypted (the site’s address begins with https://). However, an attacker would still be able to see the metadata — such as the source and destination addresses — of any traffic flowing by.
KrebsOnSecurity shared Leviathan’s research with John Kristoff, founder of dataplane.org and a PhD candidate in computer science at the University of Illinois Chicago. Kristoff said practically all user-edge network gear, including WiFi deployments, support some form of rogue DHCP server detection and mitigation, but that it’s unclear how widely deployed those protections are in real-world environments.
“However, and I think this is a key point to emphasize, an untrusted network is an untrusted network, which is why you’re usually employing the VPN in the first place,” Kristoff said. “If [the] local network is inherently hostile and has no qualms about operating a rogue DHCP server, then this is a sneaky technique that could be used to de-cloak some traffic – and if done carefully, I’m sure a user might never notice.”
According to Leviathan, there are several ways to minimize the threat from rogue DHCP servers on an unsecured network. One is using a device powered by the Android operating system, which apparently ignores DHCP option 121.
Relying on a temporary wireless hotspot controlled by a cellular device you own also effectively blocks this attack.
“They create a password-locked LAN with automatic network address translation,” the researchers wrote of cellular hot-spots. “Because this network is completely controlled by the cellular device and requires a password, an attacker should not have local network access.”
Leviathan’s Moratti said another mitigation is to run your VPN from inside of a virtual machine (VM) — like Parallels, VMware or VirtualBox. VPNs run inside of a VM are not vulnerable to this attack, Moratti said, provided they are not run in “bridged mode,” which causes the VM to replicate another node on the network.
In addition, a technology called “deep packet inspection” can be used to deny all in- and outbound traffic from the physical interface except for the DHCP and the VPN server. However, Leviathan says this approach opens up a potential “side channel” attack that could be used to determine the destination of traffic.
“This could be theoretically done by performing traffic analysis on the volume a target user sends when the attacker’s routes are installed compared to the baseline,” they wrote. “In addition, this selective denial-of-service is unique as it could be used to censor specific resources that an attacker doesn’t want a target user to connect to even while they are using the VPN.”
Moratti said Leviathan’s research shows that many VPN providers are currently making promises to their customers that their technology can’t keep.
“VPNs weren’t designed to keep you more secure on your local network, but to keep your traffic more secure on the Internet,” Moratti said. “When you start making assurances that your product protects people from seeing your traffic, there’s an assurance or promise that can’t be met.”
A copy of Leviathan’s research, along with code intended to allow others to duplicate their findings in a lab environment, is available here.
If only Patch Tuesdays came around infrequently — like total solar eclipse rare — instead of just creeping up on us each month like The Man in the Moon. Although to be fair, it would be tough for Microsoft to eclipse the number of vulnerabilities fixed in this month’s patch batch — a record 147 flaws in Windows and related software.
Yes, you read that right. Microsoft today released updates to address 147 security holes in Windows, Office, Azure, .NET Framework, Visual Studio, SQL Server, DNS Server, Windows Defender, Bitlocker, and Windows Secure Boot.
“This is the largest release from Microsoft this year and the largest since at least 2017,” said Dustin Childs, from Trend Micro’s Zero Day Initiative (ZDI). “As far as I can tell, it’s the largest Patch Tuesday release from Microsoft of all time.”
Tempering the sheer volume of this month’s patches is the middling severity of many of the bugs. Only three of April’s vulnerabilities earned Microsoft’s most-dire “critical” rating, meaning they can be abused by malware or malcontents to take remote control over unpatched systems with no help from users.
Most of the flaws that Microsoft deems “more likely to be exploited” this month are marked as “important,” which usually involve bugs that require a bit more user interaction (social engineering) but which nevertheless can result in system security bypass, compromise, and the theft of critical assets.
Ben McCarthy, lead cyber security engineer at Immersive Labs called attention to CVE-2024-20670, an Outlook for Windows spoofing vulnerability described as being easy to exploit. It involves convincing a user to click on a malicious link in an email, which can then steal the user’s password hash and authenticate as the user in another Microsoft service.
Another interesting bug McCarthy pointed to is CVE-2024-29063, which involves hard-coded credentials in Azure’s search backend infrastructure that could be gleaned by taking advantage of Azure AI search.
“This along with many other AI attacks in recent news shows a potential new attack surface that we are just learning how to mitigate against,” McCarthy said. “Microsoft has updated their backend and notified any customers who have been affected by the credential leakage.”
CVE-2024-29988 is a weakness that allows attackers to bypass Windows SmartScreen, a technology Microsoft designed to provide additional protections for end users against phishing and malware attacks. Childs said one of ZDI’s researchers found this vulnerability being exploited in the wild, although Microsoft doesn’t currently list CVE-2024-29988 as being exploited.
“I would treat this as in the wild until Microsoft clarifies,” Childs said. “The bug itself acts much like CVE-2024-21412 – a [zero-day threat from February] that bypassed the Mark of the Web feature and allows malware to execute on a target system. Threat actors are sending exploits in a zipped file to evade EDR/NDR detection and then using this bug (and others) to bypass Mark of the Web.”
Update, 7:46 p.m. ET: A previous version of this story said there were no zero-day vulnerabilities fixed this month. BleepingComputer reports that Microsoft has since confirmed that there are actually two zero-days. One is the flaw Childs just mentioned (CVE-2024-21412), and the other is CVE-2024-26234, described as a “proxy driver spoofing” weakness.
Satnam Narang at Tenable notes that this month’s release includes fixes for two dozen flaws in Windows Secure Boot, the majority of which are considered “Exploitation Less Likely” according to Microsoft.
“However, the last time Microsoft patched a flaw in Windows Secure Boot in May 2023 had a notable impact as it was exploited in the wild and linked to the BlackLotus UEFI bootkit, which was sold on dark web forums for $5,000,” Narang said. “BlackLotus can bypass functionality called secure boot, which is designed to block malware from being able to load when booting up. While none of these Secure Boot vulnerabilities addressed this month were exploited in the wild, they serve as a reminder that flaws in Secure Boot persist, and we could see more malicious activity related to Secure Boot in the future.”
For links to individual security advisories indexed by severity, check out ZDI’s blog and the Patch Tuesday post from the SANS Internet Storm Center. Please consider backing up your data or your drive before updating, and drop a note in the comments here if you experience any issues applying these fixes.
Adobe today released nine patches tackling at least two dozen vulnerabilities in a range of software products, including Adobe After Effects, Photoshop, Commerce, InDesign, Experience Manager, Media Encoder, Bridge, Illustrator, and Adobe Animate.
KrebsOnSecurity needs to correct the record on a point mentioned at the end of March’s “Fat Patch Tuesday” post, which looked at new AI capabilities built into Adobe Acrobat that are turned on by default. Adobe has since clarified that its apps won’t use AI to auto-scan your documents, as the original language in its FAQ suggested.
“In practice, no document scanning or analysis occurs unless a user actively engages with the AI features by agreeing to the terms, opening a document, and selecting the AI Assistant or generative summary buttons for that specific document,” Adobe said earlier this month.
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U.S. and U.K. authorities have seized the darknet websites run by LockBit, a prolific and destructive ransomware group that has claimed more than 2,000 victims worldwide and extorted over $120 million in payments. Instead of listing data stolen from ransomware victims who didn’t pay, LockBit’s victim shaming website now offers free recovery tools, as well as news about arrests and criminal charges involving LockBit affiliates.
Investigators used the existing design on LockBit’s victim shaming website to feature press releases and free decryption tools.
Dubbed “Operation Cronos,” the law enforcement action involved the seizure of nearly three-dozen servers; the arrest of two alleged LockBit members; the unsealing of two indictments; the release of a free LockBit decryption tool; and the freezing of more than 200 cryptocurrency accounts thought to be tied to the gang’s activities.
LockBit members have executed attacks against thousands of victims in the United States and around the world, according to the U.S. Department of Justice (DOJ). First surfacing in September 2019, the gang is estimated to have made hundreds of millions of U.S. dollars in ransom demands, and extorted over $120 million in ransom payments.
LockBit operated as a ransomware-as-a-service group, wherein the ransomware gang takes care of everything from the bulletproof hosting and domains to the development and maintenance of the malware. Meanwhile, affiliates are solely responsible for finding new victims, and can reap 60 to 80 percent of any ransom amount ultimately paid to the group.
A statement on Operation Cronos from the European police agency Europol said the months-long infiltration resulted in the compromise of LockBit’s primary platform and other critical infrastructure, including the takedown of 34 servers in the Netherlands, Germany, Finland, France, Switzerland, Australia, the United States and the United Kingdom. Europol said two suspected LockBit actors were arrested in Poland and Ukraine, but no further information has been released about those detained.
The DOJ today unsealed indictments against two Russian men alleged to be active members of LockBit. The government says Russian national Artur Sungatov used LockBit ransomware against victims in manufacturing, logistics, insurance and other companies throughout the United States.
Ivan Gennadievich Kondratyev, a.k.a. “Bassterlord,” allegedly deployed LockBit against targets in the United States, Singapore, Taiwan, and Lebanon. Kondratyev is also charged (PDF) with three criminal counts arising from his alleged use of the Sodinokibi (aka “REvil“) ransomware variant to encrypt data, exfiltrate victim information, and extort a ransom payment from a corporate victim based in Alameda County, California.
With the indictments of Sungatov and Kondratyev, a total of five LockBit affiliates now have been officially charged. In May 2023, U.S. authorities unsealed indictments against two alleged LockBit affiliates, Mikhail “Wazawaka” Matveev and Mikhail Vasiliev.
Vasiliev, 35, of Bradford, Ontario, Canada, is in custody in Canada awaiting extradition to the United States (the complaint against Vasiliev is at this PDF). Matveev remains at large, presumably still in Russia. In January 2022, KrebsOnSecurity published Who is the Network Access Broker ‘Wazawaka,’ which followed clues from Wazawaka’s many pseudonyms and contact details on the Russian-language cybercrime forums back to a 31-year-old Mikhail Matveev from Abaza, RU.
An FBI wanted poster for Matveev.
In June 2023, Russian national Ruslan Magomedovich Astamirov was charged in New Jersey for his participation in the LockBit conspiracy, including the deployment of LockBit against victims in Florida, Japan, France, and Kenya. Astamirov is currently in custody in the United States awaiting trial.
LockBit was known to have recruited affiliates that worked with multiple ransomware groups simultaneously, and it’s unclear what impact this takedown may have on competing ransomware affiliate operations. The security firm ProDaft said on Twitter/X that the infiltration of LockBit by investigators provided “in-depth visibility into each affiliate’s structures, including ties with other notorious groups such as FIN7, Wizard Spider, and EvilCorp.”
In a lengthy thread about the LockBit takedown on the Russian-language cybercrime forum XSS, one of the gang’s leaders said the FBI and the U.K.’s National Crime Agency (NCA) had infiltrated its servers using a known vulnerability in PHP, a scripting language that is widely used in Web development.
Several denizens of XSS wondered aloud why the PHP flaw was not flagged by LockBit’s vaunted “Bug Bounty” program, which promised a financial reward to affiliates who could find and quietly report any security vulnerabilities threatening to undermine LockBit’s online infrastructure.
This prompted several XSS members to start posting memes taunting the group about the security failure.
“Does it mean that the FBI provided a pentesting service to the affiliate program?,” one denizen quipped. “Or did they decide to take part in the bug bounty program? :):)”
Federal investigators also appear to be trolling LockBit members with their seizure notices. LockBit’s data leak site previously featured a countdown timer for each victim organization listed, indicating the time remaining for the victim to pay a ransom demand before their stolen files would be published online. Now, the top entry on the shaming site is a countdown timer until the public doxing of “LockBitSupp,” the unofficial spokesperson or figurehead for the LockBit gang.
“Who is LockbitSupp?” the teaser reads. “The $10m question.”
In January 2024, LockBitSupp told XSS forum members he was disappointed the FBI hadn’t offered a reward for his doxing and/or arrest, and that in response he was placing a bounty on his own head — offering $10 million to anyone who could discover his real name.
“My god, who needs me?,” LockBitSupp wrote on Jan. 22, 2024. “There is not even a reward out for me on the FBI website. By the way, I want to use this chance to increase the reward amount for a person who can tell me my full name from USD 1 million to USD 10 million. The person who will find out my name, tell it to me and explain how they were able to find it out will get USD 10 million. Please take note that when looking for criminals, the FBI uses unclear wording offering a reward of UP TO USD 10 million; this means that the FBI can pay you USD 100, because technically, it’s an amount UP TO 10 million. On the other hand, I am willing to pay USD 10 million, no more and no less.”
Mark Stockley, cybersecurity evangelist at the security firm Malwarebytes, said the NCA is obviously trolling the LockBit group and LockBitSupp.
“I don’t think this is an accident—this is how ransomware groups talk to each other,” Stockley said. “This is law enforcement taking the time to enjoy its moment, and humiliate LockBit in its own vernacular, presumably so it loses face.”
In a press conference today, the FBI said Operation Cronos included investigative assistance from the Gendarmerie-C3N in France; the State Criminal Police Office L-K-A and Federal Criminal Police Office in Germany; Fedpol and Zurich Cantonal Police in Switzerland; the National Police Agency in Japan; the Australian Federal Police; the Swedish Police Authority; the National Bureau of Investigation in Finland; the Royal Canadian Mounted Police; and the National Police in the Netherlands.
The Justice Department said victims targeted by LockBit should contact the FBI at https://lockbitvictims.ic3.gov/ to determine whether affected systems can be successfully decrypted. In addition, the Japanese Police, supported by Europol, have released a recovery tool designed to recover files encrypted by the LockBit 3.0 Black Ransomware.
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