US officials are warning Americans to switch to encrypted messaging apps to protect their private information from foreign hackers who may still be lurking in the country's telecommunications networks. This warning comes two months after a major attack on US telecom systems, which was attributed to the Chinese hacking group Salt Typhoon.

The attack, first reported in October, impacted major companies including AT&T, Verizon, T-Mobile, and Lumen Technologies. According to reports, the hackers targeted phone numbers associated with the Donald Trump and Kamala Harris campaigns, among others. Despite efforts to contain the breach, malicious actors may still be able to access sensitive information about Americans' communications from the telecom networks.

In a recent briefing, FBI and CISA officials emphasized the importance of encryption in protecting private communications. Jeff Greene, executive assistant director for cybersecurity at CISA, stressed that encryption is the most effective way to prevent hackers from intercepting and accessing sensitive information. "Encryption is your friend, whether it's on text messaging or if you have the capacity to use encrypted voice communication," Greene said. "Even if the adversary is able to intercept the data, if it is encrypted, it will make it impossible."

Greene's statement is particularly notable given the FBI's previous stance on encryption. While the agency publicly claims not to oppose encryption, it has historically pushed for tech companies to provide backdoors for law enforcement access. This has led to tensions between the FBI and tech companies, which argue that creating such backdoors would undermine the security of their products. The FBI's website states that it "does not want encryption to be weakened or compromised so that it can be defeated by malicious actors," but wants companies that "manage encrypted data to be able to decrypt that data and provide it to law enforcement only in response to U.S. legal process."

The FBI's stance on encryption has led to high-profile standoffs, such as the 2015 case involving Apple and the San Bernardino shooter's iPhone. In that instance, the FBI demanded that Apple break the encryption on the iPhone to provide access to the shooter's data, which Apple refused to do, citing concerns about user privacy. The FBI eventually found an alternative way to access the phone's contents.

In light of the recent attack, officials are now urging Americans to take proactive steps to protect their communications. This includes using end-to-end encrypted messaging apps like Signal and WhatsApp, which can obscure communications outside of the users involved in the call or text. By adopting these measures, individuals can minimize the risk of their private information falling into the hands of foreign adversaries.

The incident serves as a stark reminder of the vulnerabilities in the US telecommunications infrastructure and the need for individuals to take responsibility for their own cybersecurity. As the threat landscape continues to evolve, it is essential for policymakers, tech companies, and individuals to work together to develop effective solutions to protect sensitive information and prevent future breaches.