The Case for Limiting Your Browser Extensions

March 3, 2020
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Last week, KrebsOnSecurity reported to health insurance provider Blue Shield of California that its Web site was flagged by multiple security products as serving malicious content. Blue Shield quickly removed the unauthorized code. An investigation determined it was injected by a browser extension installed on the computer of a Blue Shield employee who’d edited the Web site in the past month.

The incident is a reminder that browser extensions — however useful or fun they may seem when you install them — typically have a great deal of power and can effectively read and/or write all data in your browsing sessions. And as we’ll see, it’s not uncommon for extension makers to sell or lease their user base to shady advertising firms, or in some cases abandon them to outright cybercriminals.

The health insurance site was compromised after an employee at the company edited content on the site while using a Web browser equipped with a once-benign but now-compromised extension which quietly injected code into the page.

The extension in question was Page Ruler, a Chrome addition with some 400,000 downloads. Page Ruler lets users measure the inch/pixel width of images and other objects on a Web page. But the extension was sold by the original developer a few years back, and for some reason it’s still available from the Google Chrome store despite multiple recent reports from people blaming it for spreading malicious code.

How did a browser extension lead to a malicious link being added to the health insurance company Web site? This compromised extension tries to determine if the person using it is typing content into specific Web forms, such as a blog post editing system like WordPress or Joomla.

In that case, the extension silently adds a request for a javascript link to the end of whatever the user types and saves on the page. When that altered HTML content is saved and published to the Web, the hidden javascript code causes a visitor’s browser to display ads under certain conditions.

Who exactly gets paid when those ads are shown or clicked is not clear, but there are a few clues about who’s facilitating this. The malicious link that set off antivirus alarm bells when people tried to visit Blue Shield California downloaded javascript content from a domain called linkojager[.]org.

The file it attempted to download — 212b3d4039ab5319ec.js — appears to be named after an affiliate identification number designating a specific account that should get credited for serving advertisements. A simple Internet search shows this same javascript code is present on hundreds of other Web sites, no doubt inadvertently published by site owners who happened to be editing their sites with this Page Ruler extension installed.

If we download a copy of that javascript file and view it in a text editor, we can see the following message toward the end of the file:

[NAME OF EXTENSION HERE]’s development is supported by advertisements that are added to some of the websites you visit. During the development of this extension, I’ve put in thousands of hours adding features, fixing bugs and making things better, not mentioning the support of all the users who ask for help.

Ads support most of the internet we all use and love; without them, the internet we have today would simply not exist. Similarly, without revenue, this extension (and the upcoming new ones) would not be possible.

You can disable these ads now or later in the settings page. You can also minimize the ads appearance by clicking on partial support button. Both of these options are available by clicking \’x\’ button in the corner of each ad. In both cases, your choice will remain in effect unless you reinstall or reset the extension.

This appears to be boilerplate text used by one or more affiliate programs that pay developers to add a few lines of code to their extensions. The opt-out feature referenced in the text above doesn’t actually work because it points to a domain that no longer resolves — thisadsfor[.]us. But that domain is still useful for getting a better idea of what we’re dealing with here.

Registration records maintained by DomainTools [an advertiser on this site] say it was originally registered to someone using the email address frankomedison1020@gmail.com. A reverse WHOIS search on that unusual name turns up several other interesting domains, including icontent[.]us.

icontent[.]us is currently not resolving either, but a cached version of it at Archive.org shows it once belonged to an advertising network called Metrext, which marketed itself as an analytics platform that let extension makers track users in real time.

An archived copy of the content once served at icontent[.]us promises “plag’n’play” capability.

“Three lines into your product and it’s in live,” iContent enthused. “High revenue per user.”

Another domain tied to Frank Medison is cdnpps[.]us, which currently redirects to the domain “monetizus[.]com.” Like its competitors, Monetizus’ site is full of grammar and spelling errors: “Use Monetizus Solutions to bring an extra value to your toolbars, addons and extensions, without loosing an audience,” the company says in a banner at the top of its site.

Be sure not to “loose” out on sketchy moneymaking activities!

Contacted by KrebsOnSecurity, Page Ruler’s original developer Peter Newnham confirmed he sold his extension to MonetizUs in 2017.

“They didn’t say what they were going to do with it but I assumed they were going to try to monetize it somehow, probably with the scripts their website mentions,” Newnham said. Continue reading →

French Firms Rocked by Kasbah Hacker?

March 2, 2020
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A large number of French critical infrastructure firms were hacked as part of an extended malware campaign that appears to have been orchestrated by at least one attacker based in Morocco, KrebsOnSecurity has learned. An individual thought to be involved has earned accolades from the likes of Apple, Dell, and Microsoft for helping to find and fix security vulnerabilities in their products.

In 2018, security intelligence firm HYAS discovered a malware network communicating with systems inside of a French national power company. The malware was identified as a version of the remote access trojan (RAT) known as njRAT, which has been used against millions of targets globally with a focus on victims in the Middle East.

Further investigation revealed the electricity provider was just one of many French critical infrastructure firms that had systems beaconing home to the malware network’s control center.

Other victims included one of France’s largest hospital systems; a French automobile manufacturer; a major French bank; companies that work with or manage networks for French postal and transportation systems; a domestic firm that operates a number of airports in France; a state-owned railway company; and multiple nuclear research facilities.

HYAS said it quickly notified the French national computer emergency team and the FBI about its findings, which pointed to a dynamic domain name system (DNS) provider on which the purveyors of this attack campaign relied for their various malware servers.

When it didn’t hear from French authorities after almost a week, HYAS asked the dynamic DNS provider to “sinkhole” the malware network’s control servers. Sinkholing is a practice by which researchers assume control over a malware network’s domains, redirecting any traffic flowing to those systems to a server the researchers control.

While sinkholing doesn’t clean up infected systems, it can prevent the attackers from continuing to harvest data from infected PCs or sending them new commands and malware updates. HYAS found that despite its notifications to the French authorities, some of the apparently infected systems were still attempting to contact the sinkholed control networks up until late 2019.

“Due to our remote visibility it is impossible for us to determine if the malware infections have been contained within the [affected] organizations,” HYAS wrote in a report summarizing their findings. “It is possible that an infected computer is beaconing, but is unable to egress to the command and control due to outbound firewall restrictions.”

About the only French critical infrastructure vertical not touched by the Kasbah hackers was the water management sector.

HYAS said given the entities compromised — and that only a handful of known compromises occurred outside of France — there’s a strong possibility this was the result of an orchestrated phishing campaign targeting French infrastructure firms. It also concluded the domains associated with this campaign were very likely controlled by a group of adversaries based in Morocco.

“What caught our attention was the nature of the victims and the fact that there were no other observed compromises outside of France,” said Sasha Angus, vice president of intelligence for HYAS. “With the exception of water management, when looking at the organizations involved, each fell within one of the verticals in France’s critical infrastructure strategic plan. While we couldn’t rule out financial crime as the actor’s potential motive, it didn’t appear that the actor leveraged any normal financial crime tools.”

‘FATAL’ ERROR

HYAS said the dynamic DNS provider shared information showing that one of the email addresses used to register a key DNS server for the malware network was tied to a domain for a legitimate business based in Morocco.

According to historic records maintained by Domaintools.com [an advertiser on this site], that email address — ing.equipepro@gmail.com — was used in 2016 to register the Web site talainine.com, a now-defunct business that offered recreational vehicle-based camping excursions just outside of a city in southern Morocco called Guelmim.

Archived copies of talainine.com indicate the business was managed by two individuals, including someone named Yassine Algangaf. A Google search for that name reveals a similarly named individual has been credited by a number of major software companies — including Apple, Dell and Microsoft — with reporting security vulnerabilities in their products.

A search on this name at Facebook turned up a page for another now-defunct business called Yamosoft.com that lists Algangaf as an owner. A cached copy of Yamosoft.com at archive.org says it was a Moroccan computer security service that specialized in security audits, computer hacking investigations, penetration testing and source code review. Continue reading →

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FCC Proposes to Fine Wireless Carriers $200M for Selling Customer Location Data

February 28, 2020
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The U.S. Federal Communications Commission (FCC) today proposed fines of more than $200 million against the nation’s four largest wireless carriers for selling access to their customers’ location information without taking adequate precautions to prevent unauthorized access to that data. While the fines would be among the largest the FCC has ever levied, critics say the penalties don’t go far enough to deter wireless carriers from continuing to sell customer location data.

The FCC proposed fining T-Mobile $91 million; AT&T faces more than $57 million in fines; Verizon is looking at more than $48 million in penalties; and the FCC said Sprint should pay more than $12 million.

An FCC statement (PDF) said “the size of the proposed fines for the four wireless carriers differs based on the length of time each carrier apparently continued to sell access to its customer location information without reasonable safeguards and the number of entities to which each carrier continued to sell such access.”

The fines are only “proposed” at this point because the carriers still have an opportunity to respond to the commission and contest the figures. The Wall Street Journal first reported earlier this week that the FCC was considering the fines.

The commission said it took action in response to a May 2018 story broken by The New York Times, which exposed how a company called Securus Technologies had been selling location data on customers of virtually any major mobile provider to law enforcement officials.

That same month, KrebsOnSecurity broke the news that LocationSmart — a data aggregation firm working with the major wireless carriers — had a free, unsecured demo of its service online that anyone could abuse to find the near-exact location of virtually any mobile phone in North America. Continue reading →

Zyxel 0day Affects its Firewall Products, Too

February 26, 2020
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On Monday, networking hardware maker Zyxel released security updates to plug a critical security hole in its network attached storage (NAS) devices that is being actively exploited by crooks who specialize in deploying ransomware. Today, Zyxel acknowledged the same flaw is present in many of its firewall products.

This week’s story on the Zyxel patch was prompted by the discovery that exploit code for attacking the flaw was being sold in the cybercrime underground for $20,000. Alex Holden, the security expert who first spotted the code for sale, said at the time the vulnerability was so “stupid” and easy to exploit that he wouldn’t be surprised to find other Zyxel products were similarly affected.

Now it appears Holden’s hunch was dead-on.

“We’ve now completed the investigation of all Zyxel products and found that firewall products running specific firmware versions are also vulnerable,” Zyxel wrote in an email to KrebsOnSecurity. “Hotfixes have been released immediately, and the standard firmware patches will be released in March.”

The updated security advisory from Zyxel states the exploit works against its UTM, ATP, and VPN firewalls running firmware version ZLD V4.35 Patch 0 through ZLD V4.35 Patch 2, and that those with firmware versions before ZLD V4.35 Patch 0 are not affected.

Zyxel’s new advisory suggests that some affected firewall product won’t be getting hotfixes or patches for this flaw, noting that the affected products listed in the advisory are only those which are “within their warranty support period.”

Indeed, while the exploit also works against more than a dozen of Zyxel’s NAS product lines, the company only released updates for NAS products that were newer than 2016. Its advice for those still using those unsupported NAS devices? “Do not leave the product directly exposed to the internet. If possible, connect it to a security router or firewall for additional protection.”

Hopefully, your vulnerable, unsupported Zyxel NAS isn’t being protected by a vulnerable, unsupported Zyxel firewall product.

CERT’s advisory on the flaw rate this vulnerability at a “10” — its most severe. My advice? If you can’t patch it, pitch it. The zero-day sales thread first flagged by Holden also hinted at the presence of post-authentication exploits in many Zyxel products, but the company did not address those claims in its security advisories.

Recent activity suggests that attackers known for deploying ransomware have been actively working to test the zero-day for use against targets. Holden said the exploit is now being used by a group of bad guys who are seeking to fold the exploit into Emotet, a powerful malware tool typically disseminated via spam that is frequently used to seed a target with malcode which holds the victim’s files for ransom.

“To me, a 0day exploit in Zyxel is not as scary as who bought it,” he said. “The Emotet guys have been historically targeting PCs, laptops and servers, but their venture now into IoT devices is very disturbing.”

Zyxel Fixes 0day in Network Storage Devices

February 24, 2020
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Patch comes amid active exploitation by ransomware gangs

Networking hardware vendor Zyxel today released an update to fix a critical flaw in many of its network attached storage (NAS) devices that can be used to remotely commandeer them. The patch comes 12 days after KrebsOnSecurity alerted the company that precise instructions for exploiting the vulnerability were being sold for $20,000 in the cybercrime underground.

Based in Taiwan, Zyxel Communications Corp. (a.k.a “ZyXEL”) is a maker of networking devices, including Wi-Fi routers, NAS products and hardware firewalls. The company has roughly 1,500 employees and boasts some 100 million devices deployed worldwide. While in many respects the class of vulnerability addressed in this story is depressingly common among Internet of Things (IoT) devices, the flaw is notable because it has attracted the interest of groups specializing in deploying ransomware at scale.

KrebsOnSecurity first learned about the flaw on Feb. 12 from Alex Holden, founder of Milwaukee-based security firm Hold Security. Holden had obtained a copy of the exploit code, which allows an attacker to remotely compromise more than a dozen types of Zyxel NAS products remotely without any help from users.

A snippet from the documentation provided by 500mhz for the Zyxel 0day.

Holden said the seller of the exploit code — a ne’er-do-well who goes by the nickname “500mhz” –is known for being reliable and thorough in his sales of 0day exploits (a.k.a. “zero-days,” these are vulnerabilities in hardware or software products that vendors first learn about when exploit code and/or active exploitation shows up online).

For example, this and previous zero-days for sale by 500mhz came with exhaustive documentation detailing virtually everything about the flaw, including any preconditions needed to exploit it, step-by-step configuration instructions, tips on how to remove traces of exploitation, and example search links that could be used to readily locate thousands of vulnerable devices.

500mhz’s profile on one cybercrime forum states that he is constantly buying, selling and trading various 0day vulnerabilities.

“In some cases, it is possible to exchange your 0day with my existing 0day, or sell mine,” his Russian-language profile reads.

The profile page of 500mhz, translated from Russian to English via Google Chrome.

PARTIAL PATCH

KrebsOnSecurity first contacted Zyxel on Feb. 12, sharing a copy of the exploit code and description of the vulnerability. When four days elapsed without any response from the vendor to notifications sent via multiple methods, this author shared the same information with vulnerability analysts at the U.S. Department of Homeland Security (DHS) and with the CERT Coordination Center (CERT/CC), a partnership between DHS and Carnegie Mellon University.

Less than 24 hours after contacting DHS and CERT/CC, KrebsOnSecurity heard back from Zyxel, which thanked KrebsOnSecurity for the alert without acknowledging its failure to respond until they were sent the same information by others.

“Thanks for flagging,” Zyxel’s team wrote on Feb. 17. “We’ve just received an alert of the same vulnerabilities from US-CERT over the weekend, and we’re now in the process of investigating. Still, we heartily appreciate you bringing it to our attention.”

Earlier today, Zyxel sent a message saying it had published a security advisory and patch for the zero-day exploit in some of its affected products. The vulnerable devices include NAS542, NAS540, NAS520, NAS326, NSA325 v2, NSA325, NSA320S, NSA320, NSA310S, NSA310, NSA221, NSA220+, NSA220, and NSA210. The flaw is designated as CVE-2020-9054.

However, many of these devices are no longer supported by Zyxel and will not be patched. Zyxel’s advice for those users is simply “do not leave the product directly exposed to the internet.”

“If possible, connect it to a security router or firewall for additional protection,” the advisory reads.

Holden said given the simplicity of the exploit — which allows an attacker to seize remote control over an affected device by injecting just two characters to the username field of the login panel for Zyxel NAS devices — it’s likely other Zyxel products may have related vulnerabilities.

“Considering how stupid this exploit is, I’m guessing this is not the only one of its class in their products,” he said.

CERT’s advisory on the flaw rates it at a “10” — its most severe. The advisory includes additional mitigation instructions, including a proof-of-concept exploit that has the ability to power down affected Zyxel devices.

Continue reading →

Hackers Were Inside Citrix for Five Months

February 19, 2020
73 Comments

Networking software giant Citrix Systems says malicious hackers were inside its networks for five months between 2018 and 2019, making off with personal and financial data on company employees, contractors, interns, job candidates and their dependents. The disclosure comes almost a year after Citrix acknowledged that digital intruders had broken in by probing its employee accounts for weak passwords.

Citrix provides software used by hundreds of thousands of clients worldwide, including most of the Fortune 100 companies. It is perhaps best known for selling virtual private networking (VPN) software that lets users remotely access networks and computers over an encrypted connection.

In March 2019, the Federal Bureau of Investigation (FBI) alerted Citrix they had reason to believe cybercriminals had gained access to the company’s internal network. The FBI told Citrix the hackers likely got in using a technique called “password spraying,” a relatively crude but remarkably effective attack that attempts to access a large number of employee accounts (usernames/email addresses) using just a handful of common passwords.

In a statement released at the time, Citrix said it appeared hackers “may have accessed and downloaded business documents,” and that it was still working to identify what precisely was accessed or stolen.

But in a letter sent to affected individuals dated Feb. 10, 2020, Citrix disclosed additional details about the incident. According to the letter, the attackers “had intermittent access” to Citrix’s internal network between Oct. 13, 2018 and Mar. 8, 2019, and that there was no evidence that the cybercrooks still remain in the company’s systems.

Citrix said the information taken by the intruders may have included Social Security Numbers or other tax identification numbers, driver’s license numbers, passport numbers, financial account numbers, payment card numbers, and/or limited health claims information, such as health insurance participant identification number and/or claims information relating to date of service and provider name.

It is unclear how many people received this letter, but the communication suggests Citrix is contacting a broad range of individuals who work or worked for the company at some point, as well as those who applied for jobs or internships there and people who may have received health or other benefits from the company by virtue of having a family member employed by the company. Continue reading →

Encoding Stolen Credit Card Data on Barcodes

February 18, 2020
56 Comments

Crooks are constantly dreaming up new ways to use and conceal stolen credit card data. According to the U.S. Secret Service, the latest scheme involves stolen card information embedded in barcodes affixed to phony money network rewards cards. The scammers then pay for merchandise by instructing a cashier to scan the barcode and enter the expiration date and card security code.

This phony reloadable rewards card conceals stolen credit card data written to a barcode. The barcode and other card data printed on the card have been obfuscated. Image: U.S. Secret Service.

Earlier this month, the Secret Service documented a recent fraud incident in Texas involving a counterfeit club membership card containing a barcode, and a card expiration date and CVV printed below the barcode.

“Located underneath the barcode are instructions to the cashier on the steps necessary to complete the transaction,” reads an alert the Secret Service sent to law enforcement agencies. “They instruct the cashier to select card payment, scan the barcode, then enter the expiration date and CVV. In this instance, the barcode was encoded with a VISA credit card number.” Continue reading →

Pay Up, Or We’ll Make Google Ban Your Ads

February 17, 2020
52 Comments

A new email-based extortion scheme apparently is making the rounds, targeting Web site owners serving banner ads through Google’s AdSense program. In this scam, the fraudsters demand bitcoin in exchange for a promise not to flood the publisher’s ads with so much bot and junk traffic that Google’s automated anti-fraud systems suspend the user’s AdSense account for suspicious traffic.

A redacted extortion email targeting users of Google’s AdSense program.

Earlier this month, KrebsOnSecurity heard from a reader who maintains several sites that receive a fair amount of traffic. The message this reader shared began by quoting from an automated email Google’s systems might send if they detect your site is seeking to benefit from automated clicks. The message continues:

“Very soon the warning notice from above will appear at the dashboard of your AdSense account undoubtedly! This will happen due to the fact that we’re about to flood your site with huge amount of direct bot generated web traffic with 100% bounce ratio and thousands of IP’s in rotation — a nightmare for every AdSense publisher. More also we’ll adjust our sophisticated bots to open, in endless cycle with different time duration, every AdSense banner which runs on your site.”

The message goes on to warn that while the targeted site’s ad revenue will be briefly increased, “AdSense traffic assessment algorithms will detect very fast such a web traffic pattern as fraudulent.”

“Next an ad serving limit will be placed on your publisher account and all the revenue will be refunded to advertisers. This means that the main source of profit for your site will be temporarily suspended. It will take some time, usually a month, for the AdSense to lift your ad ban, but if this happens we will have all the resources needed to flood your site again with bad quality web traffic which will lead to second AdSense ban that could be permanent!”

The message demands $5,000 worth of bitcoin to forestall the attack. In this scam, the extortionists are likely betting that some publishers may see paying up as a cheaper alternative to having their main source of advertising revenue evaporate.

The reader who shared this email said while he considered the message likely to be a baseless threat, a review of his recent AdSense traffic statistics showed that detections in his “AdSense invalid traffic report” from the past month had increased substantially. Continue reading →

A Light at the End of Liberty Reserve’s Demise?

February 14, 2020
26 Comments

In May 2013, the U.S. Justice Department seized Liberty Reserve, alleging the virtual currency service acted as a $6 billion financial hub for the cybercrime world. Prompted by assurances that the government would one day afford Liberty Reserve users a chance to reclaim any funds seized as part of the takedown, KrebsOnSecurity filed a claim shortly thereafter to see if and when this process might take place. This week, an investigator with the U.S. Internal Revenue Service finally got in touch to discuss my claim.

Federal officials charged that Liberty Reserve facilitated a “broad range of criminal activity, including credit card fraud, identity theft, investment fraud, computer hacking, child pornography, and narcotics trafficking.” The government says from 2006 until the service’s takedown, Liberty Reserve processed an estimated 55 million financial transactions worth more than $6 billion, with more than 600,000 accounts associated with users in the United States alone.

While it’s clear that the digital currency system for years was the go-to money-moving vehicle for many engaged in dodgy online activities, it also was favored by users primarily because it offered a relatively anonymous way to send irrevocable transfers globally with low fees.

The two stories I wrote about the closure of Liberty Reserve in 2013 remain among the most-read on this site, and have generated an enormous volume of emails from readers who saw many thousands of dollars held in legal limbo — much of it related to investments in online gaming platforms, payments to and from adult entertainment services, and various investment schemes.

The IRS official who contacted me was not authorized to be quoted in the media (and indeed did not initially realize he was speaking to a member of the press when he called). But he told me the government had recently obtained legal access to some of the funds held in overseas bank accounts that were used by Liberty Reserve, and that IRS investigators were now starting to contact people and vet any claims made in the wake of the takedown.

“We’re just getting to the point where we have received funds,” the investigator said. “We’ve started to contact people who originally contacted us, to vet their claims, make sure they weren’t involved in any illegal activity, and that the claim amounts match the records that we have.” Continue reading →

Microsoft Patch Tuesday, February 2020 Edition

February 11, 2020
56 Comments

Microsoft today released updates to plug nearly 100 security holes in various versions of its Windows operating system and related software, including a zero-day vulnerability in Internet Explorer (IE) that is actively being exploited. Also, Adobe has issued a bevy of security updates for its various products, including Flash Player and Adobe Reader/Acrobat.

A dozen of the vulnerabilities Microsoft patched today are rated “critical,” meaning malware or miscreants could exploit them remotely to gain complete control over an affected system with little to no help from the user.

Last month, Microsoft released an advisory warning that attackers were exploiting a previously unknown flaw in IE. That vulnerability, assigned as CVE-2020-0674, has been patched with this month’s release. It could be used to install malware just by getting a user to browse to a malicious or hacked Web site.

Microsoft once again fixed a critical flaw in the way Windows handles shortcut (.lnk) files (CVE-2020-0729) that affects Windows 8 and 10 systems, as well as Windows Server 2008-2012. Allan Liska, intelligence analyst at Recorded Future, says Microsoft considers exploitation of the vulnerability unlikely, but that a similar vulnerability discovered last year, CVE-2019-1280, was being actively exploited by the Astaroth trojan as recently as September.

Another flaw fixed this month in Microsoft Exchange 2010 through 2019 may merit special attention. The bug could allow attackers to exploit the Exchange Server and execute arbitrary code just by sending a specially crafted email. This vulnerability (CVE-2020-0688) is rated “important” rather than “critical,” but Liska says it seems potentially dangerous, as Microsoft identifies this as a vulnerability that is likely to be exploited.

In addition, Redmond addressed a critical issue (CVE-2020-0618) in the way Microsoft SQL Server versions 2012-2016 handle page requests.

After a several-month respite from patches for its Flash Player browser plug-in, Adobe has once again blessed us with a security update for this program (fixes one critical flaw). Thankfully, Chrome and Firefox both now disable Flash by default, and Chrome and IE/Edge auto-update the program when new security updates are available. Adobe is slated to retire Flash Player later this year. Continue reading →