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One frustrating aspect of email phishing is the frequency with which scammers fall back on tried-and-true methods that really have no business working these days. Like attaching a phishing email to a traditional, clean email message, or leveraging link redirects on LinkedIn, or abusing an encoding method that makes it easy to disguise booby-trapped Microsoft Windows files as relatively harmless documents.
KrebsOnSecurity recently heard from a reader who was puzzled over an email he’d just received saying he needed to review and complete a supplied W-9 tax form. The missive was made to appear as if it were part of a mailbox delivery report from Microsoft 365 about messages that had failed to deliver.
The reader, who asked to remain anonymous, said the phishing message contained an attachment that appeared to have a file extension of “.pdf,” but something about it seemed off. For example, when he downloaded and tried to rename the file, the right arrow key on the keyboard moved his cursor to the left, and vice versa.
The file included in this phishing scam uses what’s known as a “right-to-left override” or RLO character. RLO is a special character within unicode — an encoding system that allows computers to exchange information regardless of the language used — that supports languages written from right to left, such as Arabic and Hebrew.
Look carefully at the screenshot below and you’ll notice that while Microsoft Windows says the file attached to the phishing message is named “lme.pdf,” the full filename is “fdp.eml” spelled backwards. In essence, this is a .eml file — an electronic mail format or email saved in plain text — masquerading as a .PDF file.
“The email came through Microsoft Office 365 with all the detections turned on and was not caught,” the reader continued. “When the same email is sent through Mimecast, Mimecast is smart enough to detect the encoding and it renames the attachment to ‘___fdp.eml.’ One would think Microsoft would have had plenty of time by now to address this.”
Indeed, KrebsOnSecurity first covered RLO-based phishing attacks back in 2011, and even then it wasn’t a new trick.
Opening the .eml file generates a rendering of a webpage that mimics an alert from Microsoft about wayward messages awaiting restoration to your inbox. Clicking on the “Restore Messages” link there bounces you through an open redirect on LinkedIn before forwarding to the phishing webpage.
As noted here last year, scammers have long taken advantage of a marketing feature on the business networking site which lets them create a LinkedIn.com link that bounces your browser to other websites, such as phishing pages that mimic top online brands (but chiefly Linkedin’s parent firm Microsoft).
The landing page after the LinkedIn redirect displays what appears to be an Office 365 login page, which is naturally a phishing website made to look like an official Microsoft Office property.
In summary, this phishing scam uses an old RLO trick to fool Microsoft Windows into thinking the attached file is something else, and when clicked the link uses an open redirect on a Microsoft-owned website (LinkedIn) to send people to a phishing page that spoofs Microsoft and tries to steal customer email credentials.
According to the latest figures from Check Point Software, Microsoft was by far the most impersonated brand for phishing scams in the second quarter of 2023, accounting for nearly 30 percent of all brand phishing attempts.
An unsolicited message that arrives with one of these .eml files as an attachment is more than likely to be a phishing lure. The best advice to sidestep phishing scams is to avoid clicking on links that arrive unbidden in emails, text messages and other mediums. Most phishing scams invoke a temporal element that warns of dire consequences should you fail to respond or act quickly.
If you’re unsure whether a message is legitimate, take a deep breath and visit the site or service in question manually — ideally, using a browser bookmark to avoid potential typosquatting sites.
The U.S. government agency in charge of improving the nation’s cybersecurity posture is ordering all federal agencies to take new measures to restrict access to Internet-exposed networking equipment. The directive comes amid a surge in attacks targeting previously unknown vulnerabilities in widely used security and networking appliances.
Under a new order from the Cybersecurity and Infrastructure Security Agency (CISA), federal agencies will have 14 days to respond to any reports from CISA about misconfigured or Internet-exposed networking equipment. The directive applies to any networking devices — such as firewalls, routers and load balancers — that allow remote authentication or administration.
The order requires federal departments to limit access so that only authorized users on an agency’s local or internal network can reach the management interfaces of these devices. CISA’s mandate follows a slew of recent incidents wherein attackers exploited zero-day flaws in popular networking products to conduct ransomware and cyber espionage attacks on victim organizations.
Earlier today, incident response firm Mandiant revealed that since at least October 2022, Chinese cyber spies have been exploiting a zero-day vulnerability in many email security gateway (ESG) appliances sold by California-based Barracuda Networks to hoover up email from organizations using these devices.
Barracuda was alerted to the exploitation of a zero-day in its products in mid-May, and two days later the company pushed a security update to address the flaw in all affected devices. But last week, Barracuda took the highly unusual step of offering to replace compromised ESGs, evidently in response to malware that altered the systems in such a fundamental way that they could no longer be secured remotely with software updates.
According to Mandiant, a previously unidentified Chinese hacking group was responsible for exploiting the Barracuda flaw, and appeared to be searching through victim organization email records for accounts “belonging to individuals working for a government with political or strategic interest to [China] while this victim government was participating in high-level, diplomatic meetings with other countries.”
When security experts began raising the alarm about a possible zero-day in Barracuda’s products, the Chinese hacking group altered their tactics, techniques and procedures (TTPs) in response to Barracuda’s efforts to contain and remediate the incident, Mandiant found.
Mandiant said the attackers will continue to change their tactics and malware, “especially as network defenders continue to take action against this adversary and their activity is further exposed by the infosec community.”
Meanwhile, this week we learned more details about the ongoing exploitation of a zero-day flaw in a broad range of virtual private networking (VPN) products made by Fortinet — devices many organizations rely on to facilitate remote network access for employees.
On June 11, Fortinet released a half-dozen security updates for its FortiOS firmware, including a weakness that researchers said allows an attacker to run malware on virtually any Fortinet SSL VPN appliance. The researchers found that just being able to reach the management interface for a vulnerable Fortinet SSL VPN appliance was enough to completely compromise the devices.
“This is reachable pre-authentication, on every SSL VPN appliance,” French vulnerability researcher Charles Fol tweeted. “Patch your #Fortigate.”
In details published on June 12, Fortinet confirmed that one of the vulnerabilities (CVE-2023-27997) is being actively exploited. The company said it discovered the weakness in an internal code audit that began in January 2023 — when it learned that Chinese hackers were exploiting a different zero-day flaw in its products.
Shodan.io, the search engine made for finding Internet of Things devices, reports that there are currently more than a half-million vulnerable Fortinet devices reachable via the public Internet.
The new cybersecurity directive from CISA orders agencies to remove any networking device management interfaces from the internet by making them only accessible from an internal enterprise network (CISA recommends an isolated management network). CISA also says agencies should “deploy capabilities, as part of a Zero Trust Architecture, that enforce access control to the interface through a policy enforcement point separate from the interface itself (preferred action).”
Security experts say CISA’s directive highlights the reality that cyberspies and ransomware gangs are making it increasingly risky for organizations to expose any devices to the public Internet, because these groups have strong incentives to probe such devices for previously unknown security vulnerabilities.
The most glaring example of this dynamic can be seen in the frequency with which ransomware groups have discovered and pounced on zero-day flaws in widely-used file transfer applications. One ransomware gang in particular — Cl0p — has repeatedly exploited zero day bugs in various file transfer appliances to extort tens of millions of dollars from hundreds of ransomware victims.
On February 2, KrebsOnSecurity broke the news that attackers were exploiting a zero-day vulnerability in the GoAnywhere file transfer appliance by Fortra. By the time security updates were available to fix the vulnerability, Cl0p had already used it to steal data from more than a hundred organizations running Fortra’s appliance.
According to CISA, on May 27, Cl0p began exploiting a previously unknown flaw in MOVEit Transfer, a popular Internet-facing file transfer application. MOVEit parent Progress Software has since released security updates to address the weakness, but Cl0p claims to have already used it to compromise hundreds of victim organizations. TechCrunch has been tracking the fallout from victim organizations, which range from banks and insurance providers to universities and healthcare entities.
The always on-point weekly security news podcast Risky Business has recently been urging organizations to jettison any and all FTP appliances, noting that Cl0p (or another crime gang) is likely to visit the same treatment on other FTP appliance vendors.
But that sound advice doesn’t exactly scale for mid-tier networking devices like Barracuda ESGs or Fortinet SSL VPNs, which are particularly prominent in small to mid-sized organizations.
“It’s not like FTP services, you can’t tell an enterprise [to] turn off the VPN [because] the productivity hit of disconnecting the VPN is terminal, it’s a non-starter,” Risky Business co-host Adam Boileau said on this week’s show. “So how to mitigate the impact of having to use a domain-joined network appliance at the edge of your network that is going to get zero-day in it? There’s no good answer.”
Risky Business founder Patrick Gray said the COVID-19 pandemic breathed new life into entire classes of networking appliances that rely on code which was never designed with today’s threat models in mind.
“In the years leading up to the pandemic, the push towards identity-aware proxies and zero trust everything and moving away from this type of equipment was gradual, but it was happening,” Gray said. “And then COVID-19 hit and everybody had to go work from home, and there really was one option to get going quickly — which was to deploy VPN concentrators with enterprise features.”
Gray said the security industry had been focused on building the next generation of remote access tools that are more security-hardened, but when the pandemic hit organizations scrambled to cobble together whatever they could.
“The only stuff available in the market was all this old crap that is not QA’d properly, and every time you shake them CVEs fall out,” Gray remarked, calling the pandemic, “a shot in the arm” to companies like Fortinet and Barracuda.
“They sold so many VPNs through the pandemic and this is the hangover,” Gray said. “COVID-19 extended the life of these companies and technologies, and that’s unfortunate.”
For Cisco engineers working on Duo, having a remote-first workplace has helped them reach life goals, connect with colleagues around the world, and be intentional communicators. We understand that working remotely can be an adjustment — that’s why we’ve compiled the 10 parts of remote work that surprised our team members most and their advice for navigating the nuances. If you’re interested in being part of a remote-first workplace, check out our open positions.
Senior Engineering Leader David Rines has worked remotely for the past seven years. He’s found that Cisco’s approach to distributed teams has “enabled us to pick up the right talent, and not necessarily local talent. We are moving towards a global, follow the sun environment,” he said.
One of the aspects Rines appreciates most of this structure is getting “a widely varied set of perspectives and experiences that help build a more reliable, more robust product, which is why we’re here.”
Another benefit to having colleagues across the globe is the sharing of recipes, a perk Senior Site Reliability Engineer Bernard Ting particularly enjoys. Proactively communicating with colleagues virtually “helps you to form bonds with people from other teams. You can always learn something new about cultures elsewhere. I talk to people about food and so I’m always gathering recipes from people from all over the world,” Ting shared.
While some may fear that working remotely could lead to feelings of isolation and loneliness, a different camaraderie can flourish in the structure of our distributed teams. With colleagues across time zones, “there’s always someone there who you can reach out to help solve your problem,” Rines said.
Collaboration hours are another way Site Reliability Engineering Manager Jaya Sistla has cultivated virtual community and problem-solving. These hours are blocked off for team members to talk about what they’re working on. “The main thing is being able to ask for help so you don’t go into the rabbit hole debugging things,” Sistla said.
Ting points out that working in a distributed model allows you to really engage in virtual events and conversations. Given that the team mainly communicates through online chat, Ting has found that “forces you to see everyone as equally approachable, which has made me more comfortable reaching out to people from anywhere in the world.”
For folks sharing an office, collaboration can happen through casual chats over coffee. When facing a challenge, you can ask your neighbor for support. While ideally virtual communication could have a similar cadence and spontaneity, the logistics of remote and distributed work require intentionality and being proactive in connecting with colleagues as people and as co-workers.
When Ting first started working remotely, he felt that every meeting needed to be formal and have a business objective. By sharing his feelings with his manager, he was reassured that “socializing is a very important part of teamwork, because if you don’t have a good relationship with your colleagues you’re not going to be able to have healthy discussions, healthy conflict or be able to critique each other when the situation arises.”
Since that conversation, Ting has been more proactive about catching up with colleagues, which can include sharing a coffee over video chat. Duo’s “coffee roulette” formalizes the process as every month, employees who opt in can be randomly paired up for a quick half-hour chat focused exclusively on socializing. Ting has found being proactive about socializing virtually helpful. “It’s made me more intentional with my time and really treasure the social experience you can get,” he said.
Some folks may be concerned that without a manager observing their efforts and work ethic day in and day out, it may be harder to recognize accomplishments and challenges. Ting found that within his team “when you work on projects and in your one-on-ones with your managers, they’re always very intentional about learning what you’ve been doing and seeing what your progress is like on certain projects. I’ve been asked, ‘How do you think you can improve? What are some of the things you’ve been doing outside of the team work?’”
To cultivate cross-team collaboration and education, there are thoughtfully planned virtual lunch and learns. “We schedule training sessions and common meetings at times that are flexible for everyone. If it has to be repeated, we do it so people can comfortably attend rather than stretching themselves and attending at odd hours,” Sistla said.
For Software Engineer Nick Aspinall, an important and fun part of working remotely is keeping in touch with virtual messaging. One unique perk has been getting to create and customize emojis with team members including a few of himself in “various ridiculous states,” he said.
Connecting with colleagues on themed channels focused on personal and professional interests from coffee to pets “makes it really cool because you can meet people across different teams and still get some of the feeling of rubbing elbows that you get when you’re in the office,” Aspinall said. Participating in these virtual conversations boosts morale while also providing an endless supply of cute animal pics.
Given the multi-faceted nature of our work and the importance of consistent information sharing, having different communication channels and formats to communicate data with varying degrees of complexity is vital. Having information readily accessible, accurate and updated is particularly necessary in a field like cybersecurity.
Senior Software Engineer Mario Lopez finds that the variety of information sources contributes to an easeful remote working experience. For instance, for complex architecture decisions or detailing, Duo’s Wiki is the best source.
Software Engineer Hanna Fernandez has benefited from chat channels dedicated to design and engineering topics to “see what everyone’s up to and what thoughts people have,” she said. Sista pointed out these are great places to ask questions and open up dialogue to solve problems.
Our culture is “video-on,” meaning that it is preferred that during video meetings, as much as possible, attendees have their cameras on. Lopez loves this because “you get a bit of that personal human element.”
“We’re all people behind these screens. You definitely get some of people’s personality through text, but you get it more when you actually see them. It’s infectious when you see someone smiling. You’ve got to smile back,” he shared (while we both smiled).
When Fernandez started at Cisco, she was advised to schedule individual meetings with everyone she would be working with on every team that she joined. That suggestion is one she’s applied even virtually.
“It’s a great strategy because I already know that my team is super talented and very smart, but this way I also get to know them as humans beyond their roles,” Fernandez said. Fernandez also finds it important to check in with co-workers and ask how they’re feeling and how their time off was. “I know a lot of people hate small talk, but it’s not just small talk. I’m genuinely interested in how my co-workers are doing.”
One of Ting’s biggest goals was buying his first house in the countryside outside of London. By working remotely, Ting has flexibility in his location which allowed him to achieve his goal of buying a house and settling down with his partner, while giving their dogs the space they need to be dogs.
When transitioning from fully remote to hybrid, it’s important to recognize that there will be some shifts to get accustomed to. As the structures of remote, distributed and hybrid work evolve, it’s important to stay flexible and notice what’s possible through multiple modalities of team building. Many teams have enjoyed in-person gatherings and connecting through virtual lunches and team games when remote.
Fernandez has had multiple roles with multiple structures at Cisco. As an intern, she was fully in person and shared desk space with other interns who collaborated on full stack engineering. While working in finance IT, Fernandez was hybrid and many of her colleagues were distributed among multiple offices. The pandemic began while she was in a DevOps role, forcing her to maintain boundaries around her work time while working fully remotely. In her current role working on Duo, Fernandez is completely remote but advocates for in-person events if possible, because “humans are social creatures who want to see each other’s faces in real life once in a while.”
For Aspinall, “when we did come back to the office, there was a bit of an adjustment period where you were overstimulated from the office.” He also wanted to ensure team members who were 100% remote were fully included. Now he sees that while half his team is fully remote and the other half is hybrid, “that doesn’t stop anyone from doing anything. All of our meetings feel the same. They’re all seamless.”
If you’re interested in joining our team from wherever you are in the world, check out our open roles.
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