While disruptive attacks are on the rise, the time between a company being compromised and discovery of the attack is continuing to drop, according to a new FireEye report.

FireEye's seventh annual Mandiant M-Trends report was compiled from advanced threat investigations conducted by Mandiant's leading consultants in 2015, and details the leading cyber trends and tactics threat actors used to compromise businesses and steal data.

“In 2015, we continued to be reminded that there is no such thing as perfect security,” sys Kevin Mandia, FireEye SVP and president.

A key finding of the report was the fact that the time it takes organisations to discover compromises continues to drop. The median number of days attackers were present on a victim's network before being discovered dropped to 146 days in 2015 from 205 days in 2014; however, breaches can go undetected for years, the report finds.

Furthermore, breaches continue to be discovered by third-party sources. Mandiant's investigations of attacks show that external identification takes longer, with an average of 319.5 days from compromise to discovery. Internal discovery takes an average of 56 days, according to FireEye.

The report also found disruptive attacks are becoming more common. Over the past year, Mandiant responded to incidents where attackers destroyed critical business systems, leaked confidential data, held companies for ransom, and taunted executives. Some attackers were motivated by money, some claimed to be retaliating for political purposes, and others simply wanted to cause embarrassment.

“Based on the significant number of incidents that Mandiant investigated in 2015, threat actors are finding inventive and disruptive ways to skirt even the best defences, resulting in informational, financial and reputational loss,” Mandia says.