Don’t Let Zombie Zoom Links Drag You Down

Many organizations — including quite a few Fortune 500 firms — have exposed web links that allow anyone to initiate a Zoom video conference meeting as a valid employee. These company-specific Zoom links, which include a permanent user ID number and an embedded passcode, can work indefinitely and expose an organization’s employees, customers or partners to phishing and other social engineering attacks.

Image: @Pressmaster on Shutterstock.

At issue is the Zoom Personal Meeting ID (PMI), which is a permanent identification number linked to your Zoom account and serves as your personal meeting room available around the clock. The PMI portion forms part of each new meeting URL created by that account, such as:

zoom.us/j/5551112222

Zoom has an option to include an encrypted passcode within a meeting invite link, which simplifies the process for attendees by eliminating the need to manually enter the passcode. Following the previous example, such a link might look something like this:

zoom.us/j/5551112222/pwd=jdjsklskldklsdksdklsdkll

Using your PMI to set up new meetings is convenient, but of course convenience often comes at the expense of security. Because the PMI remains the same for all meetings, anyone with your PMI link can join any ongoing meeting unless you have locked the meeting or activated Zoom’s Waiting Room feature.

Including an encrypted passcode in the Zoom link definitely makes it easier for attendees to join, but it might open your meetings to unwanted intruders if not handled responsibly. Particularly if that Zoom link is somehow indexed by Google or some other search engine, which happens to be the case for thousands of organizations.

Armed with one of these links, an attacker can create meetings and invite others using the identity of the authorized employee. And many companies using Zoom have made it easy to find recently created meeting links that include encrypted passcodes, because they have dedicated subdomains at Zoom.us.

Using the same method, KrebsOnSecurity also found working Zoom meeting links for The National Football League (NFL), LinkedIn, Oracle, Humana, Disney, Warner Bros, and Uber. And that was from just a few minutes of searching. And to illustrate the persistence of some of these Zoom links, Archive.org says several of the links were first created as far back as 2020 and 2021.

KrebsOnSecurity received a tip about the Zoom exposures from Charan Akiri, a researcher and security engineer at Reddit. In April 2023, this site featured research by Akiri showing that many public Salesforce websites were leaking private data, including banks and healthcare organizations (Akiri said Salesforce also had these open Zoom meeting links before he notified them).

The Zoom links that exposed working meeting rooms all had enabled the highlighted option.

Akiri said the misuse of PMI links, particularly those with passcodes embedded, can give unauthorized individuals access to meetings.

“These one-click links, which are not subject to expiration or password requirement, can be exploited by attackers for impersonation,” Akiri said. “Attackers exploiting these vulnerabilities can impersonate companies, initiating meetings unknowingly to users. They can contact other employees or customers while posing as the company, gaining unauthorized access to confidential information, potentially for financial gain, recruitment, or fraudulent advertising campaigns.”

Akiri said he built a simple program to crawl the web for working Zoom meeting links from different organizations, and so far it has identified thousands of organizations with these perfectly functional zombie Zoom links.

According to Akiri, here are several tips for using Zoom links more safely:

Don’t Use Personal Meeting ID for Public Meetings: Your Personal Meeting ID (PMI) is the default meeting that launches when you start an ad hoc meeting. Your PMI doesn’t change unless you change it yourself, which makes it very useful if people need a way to reach you. But for public meetings, you should always schedule new meetings with randomly generated meeting IDs. That way, only invited attendees will know how to join your meeting. You can also turn off your PMI when starting an instant meeting in your profile settings.

Require a Passcode to Join: You can take meeting security even further by requiring a passcode to join your meetings. This feature can be applied to both your Personal Meeting ID, so only those with the passcode will be able to reach you, and to newly scheduled meetings. To learn all the ways to add a passcode for your meetings, see this support article.

Only Allow Registered or Domain Verified Users: Zoom can also give you peace of mind by letting you know exactly who will be attending your meeting. When scheduling a meeting, you can require attendees to register with their email, name, and custom questions. You can even customize your registration page with a banner and logo. By default, Zoom also restricts participants to those who are logged into Zoom, and you can even restrict it to Zoom users whose email address uses a certain domain.

Further reading: How to Keep Uninvited Guests Out of Your Zoom Meeting

Update 12:33 p.m.: The list of affected organizations was updated, because several companies listed apparently only exposed links that let anyone connect to existing, always-on meeting rooms — not initiate and completely control a Zoom meeting. The real danger with the zombie links described above is that anyone can find and use them to create new meetings and invite others.

Many Public Salesforce Sites are Leaking Private Data

A shocking number of organizations — including banks and healthcare providers — are leaking private and sensitive information from their public Salesforce Community websites, KrebsOnSecurity has learned. The data exposures all stem from a misconfiguration in Salesforce Community that allows an unauthenticated user to access records that should only be available after logging in.

A researcher found DC Health had five Salesforce Community sites exposing data.

Salesforce Community is a widely-used cloud-based software product that makes it easy for organizations to quickly create websites. Customers can access a Salesforce Community website in two ways: Authenticated access (requiring login), and guest user access (no login required). The guest access feature allows unauthenticated users to view specific content and resources without needing to log in.

However, sometimes Salesforce administrators mistakenly grant guest users access to internal resources, which can cause unauthorized users to access an organization’s private information and lead to potential data leaks.

Until being contacted by this reporter on Monday, the state of Vermont had at least five separate Salesforce Community sites that allowed guest access to sensitive data, including a Pandemic Unemployment Assistance program that exposed the applicant’s full name, Social Security number, address, phone number, email, and bank account number.

This misconfigured Salesforce Community site from the state of Vermont was leaking pandemic assistance loan application data, including names, SSNs, email address and bank account information.

Vermont’s Chief Information Security Officer Scott Carbee said his security teams have been conducting a full review of their Salesforce Community sites, and already found one additional Salesforce site operated by the state that was also misconfigured to allow guest access to sensitive information.

“My team is frustrated by the permissive nature of the platform,” Carbee said.

Carbee said the vulnerable sites were all created rapidly in response to the Coronavirus pandemic, and were not subjected to their normal security review process.

“During the pandemic, we were largely standing up tons of applications, and let’s just say a lot of them didn’t have the full benefit of our dev/ops process,” Carbee said. “In our case, we didn’t have any native Salesforce developers when we had to suddenly stand up all these sites.”

Earlier this week, KrebsOnSecurity notified Columbus, Ohio-based Huntington Bank that its recently acquired TCF Bank had a Salesforce Community website that was leaking documents related to commercial loans. The data fields in those loan applications included name, address, full Social Security number, title, federal ID, IP address, average monthly payroll, and loan amount.

Huntington Bank has disabled the leaky TCF Bank Salesforce website. Matthew Jennings, deputy chief information security officer at Huntington, said the company was still investigating how the misconfiguration occurred, how long it lasted, and how many records may have been exposed.

KrebsOnSecurity learned of the leaks from security researcher Charan Akiri, who said he wrote a program that identified hundreds of other organizations running misconfigured Salesforce pages. But Akiri said he’s been wary of probing too far, and has had difficulty getting responses from most of the organizations he has notified to date.

“In January and February 2023, I contacted government organizations and several companies, but I did not receive any response from these organizations,” Akiri said. “To address the issue further, I reached out to several CISOs on LinkedIn and Twitter. As a result, five companies eventually fixed the problem. Unfortunately, I did not receive any responses from government organizations.”

The problem Akiri has been trying to raise awareness about came to the fore in August 2021, when security researcher Aaron Costello published a blog post explaining how misconfigurations in Salesforce Community sites could be exploited to reveal sensitive data (Costello subsequently published a follow-up post detailing how to lock down Salesforce Community sites).

On Monday, KrebsOnSecurity used Akiri’s findings to notify Washington D.C. city administrators that at least five different public DC Health websites were leaking sensitive information. One DC Health Salesforce Community website designed for health professionals seeking to renew licenses with the city leaked documents that included the applicant’s full name, address, Social Security number, date of birth, license number and expiration, and more.

Akiri said he notified the Washington D.C. government in February about his findings, but received no response. Reached by KrebsOnSecurity, interim Chief Information Security Officer Mike Rupert initially said the District had hired a third party to investigate, and that the third party confirmed the District’s IT systems were not vulnerable to data loss from the reported Salesforce configuration issue.

But after being presented with a document including the Social Security number of a health professional in D.C. that was downloaded in real-time from the DC Health public Salesforce website, Rupert acknowledged his team had overlooked some configuration settings.

Washington, D.C. health administrators are still smarting from a data breach earlier this year at the health insurance exchange DC Health Link, which exposed personal information for more than 56,000 users, including many members of Congress.

That data later wound up for sale on a top cybercrime forum. The Associated Press reports that the DC Health Link breach was likewise the result of human error, and said an investigation revealed the cause was a DC Health Link server that was “misconfigured to allow access to the reports on the server without proper authentication.”

Salesforce says the data exposures are not the result of a vulnerability inherent to the Salesforce platform, but they can occur when customers’ access control permissions are misconfigured.

“As previously communicated to all Experience Site and Sites customers, we recommend utilizing the Guest User Access Report Package to assist in reviewing access control permissions for unauthenticated users,” reads a Salesforce advisory from Sept. 2022. “Additionally, we suggest reviewing the following Help article, Best Practices and Considerations When Configuring the Guest User Profile.”

In a written statement, Salesforce said it is actively focused on data security for organizations with guest users, and that it continues to release “robust tools and guidance for our customers,” including:

Guest User Access Report 

Control Which Users Experience Cloud Site Users Can See

Best Practices and Considerations When Configuring the Guest User Profile

“We’ve also continued to update our Guest User security policies, beginning with our Spring ‘21 release with more to come in Summer ‘23,” the statement reads. “Lastly, we continue to proactively communicate with customers to help them understand the capabilities available to them, and how they can best secure their instance of Salesforce to meet their security, contractual, and regulatory obligations.”