A recent phishing campaign involving the use of SMS messages to lure potential victims into disclosing their bank-account access credentials is the latest evidence of growing attacker interest in users of mobile apps.
Lookout, which tracked the threat, Friday described it as impacting mobile users in dozens of countries, including the US. Among those targeted were customers of Chase, HSBC, TD, Scotiabank, and CIBC banks. The campaign appears to have started in June 2019 but is currently offline.
The mobile security vendor said it detected at least 4,000 unique IP addresses belonging to mobile users who appear to have fallen for the scam. Lookout said it is not sure how the victims were impacted financially because of a lack of visibility into how the attackers might have actually used the compromised credentials.
But campaigns like these are a clear warning for mobile users, says Apurva Kumar, staff security intelligence engineer at Lookout. "Mobile phishing is on the rise," Kumar says. "The attack was entirely mobile-focused, from delivering messages via SMS to rendering the phishing sites as mobile banking logins."
For bad actors, mobile phishing is an attractive attack vector because it is often easier to obfuscate details of a scam on the mobile form factor, she says. With the increased use of multifactor authentication for signing into many apps, consumers have grown accustomed to banks communicating with them via SMS and therefore are less likely to scrutinize the messages as carefully as they should.
Mobile devices are also attractive targets because of the amount of sensitive data they hold, Kumar says. "Many end users are still unaware that mobile phishing exists or is even a risk, even though they may be wary of email phishing attacks," she says.
Malicious mobile apps posing as legitimate apps are another growing problem for consumers, especially for those using Android devices. In a recent report, Upstream said it had identified some 98,000 malicious Android apps and some 43 million infected Android smartphone and tablets in 2019. In most cases, the malicious mobile apps were being used to perpetuate ad fraud on a massive and global scale. And troublingly, Upstream found that 32% of the most active malicious apps it blocked last year were available through Google's official mobile app store.
According to Lookout, the SMS messages used in the recent phishing campaign spoofed the login pages of various banks in an effort to capture credentials and other sensitive information, such as answers to security questions for verifying the user's identity.
The threat actors used an automated off-the-shelf SMS tool to create unique phishing messages for customers of different banks and then sent the message out in mass volume. Lookout said it identified over 200 phishing pages imitating bank login pages that were used in the campaign.
"This is a phishing-by-the-numbers attack, blasting out as many messages as possible in an effort to get even a 1% response," Kumar says. It was a mass sending of untargeted text messages to mobile users with hopes of convincing a small percent of the recipients to enter their credentials, she notes.
Lookout hasn't been able to identify the threat actor behind the campaign, but there's nothing to suggest it was necessarily a sophisticated group considering it was launched from an off-the-shelf phishing kit. "It could be literally anyone, anywhere, which represents the risk from these kits being sold on the web," Kumar says.
Check out The Edge, Dark Reading's new section for features, threat data, and in-depth perspectives. Today's featured story: "Coronavirus Raises New Business Continuity, Phishing Challenges for InfoSec"