Apple is urging users who are still running an outdated version of iOS to update their iPhones to secure against web-based attacks carried out via powerful exploit kits like Coruna and DarkSword.
These attacks employ malicious web content to target out-of-date versions of iOS, triggering an infection chain that leads to the theft of sensitive data.
"For example, if you're using an older version of iOS and were to click a malicious link or visit a compromised website, the data on your iPhone might be at risk of being stolen," Apple said in a support document.