ConnectWise Quietly Patches Flaw That Helps Phishers

ConnectWise, which offers a self-hosted, remote desktop software application that is widely used by Managed Service Providers (MSPs), is warning about an unusually sophisticated phishing attack that can let attackers take remote control over user systems when recipients click the included link. The warning comes just weeks after the company quietly patched a vulnerability that makes it easier for phishers to launch these attacks.

A phishing attack targeting MSP customers using ConnectWise.

ConnectWise Control is extremely popular among MSPs that manage, protect and service large numbers of computers remotely for client organizations. Their product provides a dynamic software client and hosted server that connects two or more computers together, and provides temporary or persistent remote access to those client systems.

When a support technician wants to use it to remotely administer a computer, the ConnectWise website generates an executable file that is digitally signed by ConnectWise and downloadable by the client via a hyperlink.

When the remote user in need of assistance clicks the link, their computer is then directly connected to the computer of the remote administrator, who can then control the client’s computer as if they were seated in front of it.

While modern Microsoft Windows operating systems by default will ask users whether they want to run a downloaded executable file, many systems set up for remote administration by MSPs disable that user account control feature for this particular application.

In October, security researcher Ken Pyle alerted ConnectWise that their client executable file gets generated based on client-controlled parameters. Meaning, an attacker could craft a ConnectWise Control client download link that would bounce or proxy the remote connection from the MSP’s servers to a server that the attacker controls.

This is dangerous because many organizations that rely on MSPs to manage their computers often set up their networks so that only remote assistance connections coming from their MSP’s networks are allowed.

Using a free ConnectWise trial account, Pyle showed the company how easy it was to create a client executable that is cryptographically signed by ConnectWise and can bypass those network restrictions by bouncing the connection through an attacker’s ConnectWise Control server.

“You as the attacker have full control over the link’s parameters, and that link gets injected into an executable file that is downloaded by the client through an unauthenticated Web interface,” said Pyle, a partner and exploit developer at the security firm Cybir. “I can send this link to a victim, they will click this link, and their workstation will connect back to my instance via a link on your site.”

A composite of screenshots researcher Ken Pyle put together to illustrate the ScreenConnect vulnerability.

On Nov. 29, roughly the same time Pyle published a blog post about his findings, ConnectWise issued an advisory warning users to be on guard against a new round email phishing attempts that mimic legitimate email alerts the company sends when it detects unusual activity on a customer account.

“We are aware of a phishing campaign that mimics ConnectWise Control New Login Alert emails and has the potential to lead to unauthorized access to legitimate Control instances,” the company said.

ConnectWise said it released software updates last month that included new protections against the misdirection vulnerability that Pyle reported.  But the company said there is no reason to believe the phishers they warned about are exploiting any of the issues reported by Pyle.

“Our team quickly triaged the report and determined the risk to partners to be minimal,” said Patrick Beggs, ConnectWise’s chief information security officer. “Nevertheless, the mitigation was simple and presented no risk to partner experience, so we put it into the then-stable 22.8 build and the then-canary 22.9 build, which were released as part of our normal release processes. Due to the low severity of the issue, we didn’t (and don’t plan to) issue a security advisory or alert, since we reserve those notifications for serious security issues.”

Beggs said the phishing attacks that sparked their advisory stemmed from an instance that was not hosted by ConnectWise.

“So we can confirm they are unrelated,” he said. “Unfortunately, phishing attacks happen far too regularly across a variety of industries and products. The timing of our advisory and Mr. Pyle’s blog were coincidental. That said, we’re all for raising more awareness of the seriousness of phishing attacks and the general importance of staying alert and aware of potentially dangerous content.”

The ConnectWise advisory warned users that before clicking any link that appears to come from their service, users should validate the content includes “domains owned by trusted sources,” and “links to go to places you recognize.”

But Pyle said this advice is not terribly useful for customers targeted in his attack scenario because the phishers can send emails directly from ConnectWise, and the short link that gets presented to the user is a wildcard domain that ends in ConnectWise Control’s own domain name — screenconnect.com. What’s more, examining the exceedingly long link generated by ConnectWise’s systems offers few insights to the average user.

“It’s signed by ConnectWise and comes from them, and if you sign up for a free trial instance, you can email people invites directly from them,” Pyle said.

ConnectWise’s warnings come amid breach reports from another major provider of remote support technologies: GoTo disclosed on Nov. 30 that it is investigating a security incident involving “unusual activity within our development environment and third-party cloud storage services. The third-party cloud storage service is currently shared by both GoTo and its affiliate, the password manager service LastPass.

In its own advisory on the incident, LastPass said they believe the intruders leveraged information stolen during a previous intrusion in August 2022 to gain access to “certain elements of our customers’ information.”  However, LastPass maintains that its “customer passwords remain safely encrypted due to LastPass’s Zero Knowledge architecture.”

In short, that architecture means if you lose or forget your all-important master LastPass password — the one needed to unlock access to all of your other passwords stored with them — LastPass can’t help you with that, because they don’t store it. But that same architecture theoretically means that hackers who might break into LastPass’s networks can’t access that information either.

Update, 7:25 p.m. ET: Included statement from ConnectWise CISO.

Sounding the Alarm on Emergency Alert System Flaws

The Department of Homeland Security (DHS) is urging states and localities to beef up security around proprietary devices that connect to the Emergency Alert System — a national public warning system used to deliver important emergency information, such as severe weather and AMBER alerts. The DHS warning came in advance of a workshop to be held this weekend at the DEFCON security conference in Las Vegas, where a security researcher is slated to demonstrate multiple weaknesses in the nationwide alert system.

A Digital Alert Systems EAS encoder/decoder that Pyle said he acquired off eBay in 2019. It had the username and password for the system printed on the machine.

The DHS warning was prompted by security researcher Ken Pyle, a partner at security firm Cybir. Pyle said he started acquiring old EAS equipment off of eBay in 2019, and that he quickly identified a number of serious security vulnerabilities in a device that is broadly used by states and localities to encode and decode EAS alert signals.

“I found all kinds of problems back then, and reported it to the DHS, FBI and the manufacturer,” Pyle said in an interview with KrebsOnSecurity. “But nothing ever happened. I decided I wasn’t going to tell anyone about it yet because I wanted to give people time to fix it.”

Pyle said he took up the research again in earnest after an angry mob stormed the U.S. Capitol on Jan. 6, 2021.

“I was sitting there thinking, ‘Holy shit, someone could start a civil war with this thing,”’ Pyle recalled. “I went back to see if this was still a problem, and it turns out it’s still a very big problem. So I decided that unless someone actually makes this public and talks about it, clearly nothing is going to be done about it.”

The EAS encoder/decoder devices Pyle acquired were made by Lyndonville, NY-based Digital Alert Systems (formerly Monroe Electronics, Inc.), which issued a security advisory this month saying it released patches in 2019 to fix the flaws reported by Pyle, but that some customers are still running outdated versions of the device’s firmware. That may be because the patches were included in version 4 of the firmware for the EAS devices, and many older models apparently do not support the new software.

“The vulnerabilities identified present a potentially serious risk, and we believe both were addressed in software updates issued beginning Oct 2019,” EAS said in a written statement. “We also provided attribution for the researcher’s responsible disclosure, allowing us to rectify the matters before making any public statements. We are aware that some users have not taken corrective actions and updated their software and should immediately take action to update the latest software version to ensure they are not at risk. Anything lower than version 4.1 should be updated immediately. On July 20, 2022, the researcher referred to other potential issues, and we trust the researcher will provide more detail. We will evaluate and work to issue any necessary mitigations as quickly as possible.”

But Pyle said a great many EAS stakeholders are still ignoring basic advice from the manufacturer, such as changing default passwords and placing the devices behind a firewall, not directly exposing them to the Internet, and restricting access only to trusted hosts and networks.

Pyle, in a selfie that is heavily redacted because the EAS device behind him had its user credentials printed on the lid.

Pyle said the biggest threat to the security of the EAS is that an attacker would only need to compromise a single EAS station to send out alerts locally that can be picked up by other EAS systems and retransmitted across the nation.

“The process for alerts is automated in most cases, hence, obtaining access to a device will allow you to pivot around,” he said. “There’s no centralized control of the EAS because these devices are designed such that someone locally can issue an alert, but there’s no central control over whether I am the one person who can send or whatever. If you are a local operator, you can send out nationwide alerts. That’s how easy it is to do this.”

One of the Digital Alert Systems devices Pyle sourced from an electronics recycler earlier this year was non-functioning, but whoever discarded it neglected to wipe the hard drive embedded in the machine. Pyle soon discovered the device contained the private cryptographic keys and other credentials needed to send alerts through Comcast, the nation’s third-largest cable company.

“I can issue and create my own alert here, which has all the valid checks or whatever for being a real alert station,” Pyle said in an interview earlier this month. “I can create a message that will start propagating through the EAS.”

Comcast told KrebsOnSecurity that “a third-party device used to deliver EAS alerts was lost in transit by a trusted shipping provider between two Comcast locations and subsequently obtained by a cybersecurity researcher.

“We’ve conducted a thorough investigation of this matter and have determined that no customer data, and no sensitive Comcast data, were compromised,” Comcast spokesperson David McGuire said.

The company said it also confirmed that the information included on the device can no longer be used to send false messages to Comcast customers or used to compromise devices within Comcast’s network, including EAS devices.

“We are taking steps to further ensure secure transfer of such devices going forward,” McGuire said. “Separately, we have conducted a thorough audit of all EAS devices on our network and confirmed that they are updated with currently available patches and are therefore not vulnerable to recently reported security issues. We’re grateful for the responsible disclosure and to the security research community for continuing to engage and share information with our teams to make our products and technologies ever more secure. Mr. Pyle informed us promptly of his research and worked with us as we took steps to validate his findings and ensure the security of our systems.”

The user interface for an EAS device.

Unauthorized EAS broadcast alerts have happened enough that there is a chronicle of EAS compromises over at fandom.com. Thankfully, most of these incidents have involved fairly obvious hoaxes.

According to the EAS wiki, in February 2013, hackers broke into the EAS networks in Great Falls, Mt. and Marquette, Mich. to broadcast an alert that zombies had risen from their graves in several counties. In Feb. 2017, an EAS station in Indiana also was hacked, with the intruders playing the same “zombies and dead bodies” audio from the 2013 incidents.

“On February 20 and February 21, 2020, Wave Broadband’s EASyCAP equipment was hacked due to the equipment’s default password not being changed,” the Wiki states. “Four alerts were broadcasted, two of which consisted of a Radiological Hazard Warning and a Required Monthly Test playing parts of the Hip Hop song Hot by artist Young Thug.”

In January 2018, Hawaii sent out an alert to cell phones, televisions and radios, warning everyone in the state that a missile was headed their way. It took 38 minutes for Hawaii to let people know the alert was a misfire, and that a draft alert was inadvertently sent. The news video clip below about the 2018 event in Hawaii does a good job of walking through how the EAS works.