Yahoo Mail banned from US Congress due to increased ransomware attacks on the House network

The US Congressional IT department has banned access to Yahoo Mail in the House network due to increase in ransomware attacks in the past few days. As part of an effort to avoid malicious attacks on the network, several other apps including a bunch of Google Apps have also been blocked until they can be deemed safe.

Gizmodo reports that it has been able to access an e-mail from the House technology service desk warning representatives of increased ransomware attacks on the House network. It specifically tells the members that hackers are trying to target third-party email and other apps, like YahooMail and Gmail, and that YahooMail will be blocked with immediate effect until further notice.

The e-mail reads as below:

In the past 48 hours, the House Information Security Office has seen an increase of attacks on the House Network using third party, web-based mail applications such as YahooMail, Gmail, etc. The attacks are focused on putting "ransomware" on users' computers.

When a user clicks on the link in the attack e-mail, the malware encrypts all files on that computer, including shared files, making them unusable until a "ransom" is paid. The recent attacks have focused on using .js files attached as zip files to e-mail that appear to come from known senders. The primary focus appears to be through YahooMail at this time.

The House Information Security Office is taking a number of steps to address this specific attack. As part of that effort, we will be blocking access to YahooMail on the House Network until further notice. We are making every effort to put other mitigating protections in place so that we can restore full access as soon as possible.

Please do your part to help us address this recent attack and protect the House Network going forward by following proper cyber practices at all times. Phishing e-mails can look very legitimate and appear to come from known senders. Be very careful about clicking on attachments or links in e-mails, particularly when you are using non-House e-mail systems.

The e-mail clearly mentions that the type of attacks is indeed ransomware related. Ransomware attacks involve injection of malicious software into systems designed to block access until a sum of money is paid. Recently, some hospitals and schools in the US were hit by similar attacks.

In response to Yahoo being blocked, the company said: "We take the security of our users very seriously, and we're collaborating closely with House IT staff to ensure that they have the right solutions in place to best protect their accounts."

House officials declined to confirm whether any ransomware attack had already taken place due to which they were taking this extreme step. Unlike corporates, a ransomware attack on the legislature goes beyond financial loss and could expose bills, memos, emails and even government employee information.