Microsoft took aim at deceptive software in its latest semi-annual Security Intelligence Report, noting that the addition of two popular, but deceptive, programs to its malware-removal program caused a trebling of the company's malware detections in the fourth quarter of 2013.
The report, released May 7, showed that the number of computers cleaned with Microsoft's Malware Removal Tool jumped to 17.8 systems per 1,000 scanned in the fourth quarter of 2013, up from 5.6 in the third quarter. The jump represents the largest quarter-to-quarter increase in the infection rate ever measured by the company and happened while there was little change in the proportion of computers that encountered an attack.
The increase is largely due to Microsoft adding signatures for two deceptive programs, and the increase in ransomware programs, Holly Stewart, senior program manager of Microsoft's Malware Protection Center, told eWEEK.
"While the use of deceptive tactics is not new, it dramatically increased in the second half of 2013," she said.
Deceptive downloads include programs that appear to install a benign utility or plugin, but instead load malicious functionality. Two main families of malware accounted for the massive increase in the fourth quarter, according to Microsoft, because the company added both the pre-existing programs to its Malware Removal Tool.
One program, Rotbrow or "Browser Protector," claims to protect a user's system from browser add-ons, but instead installs unwanted software. Another, dubbed Brantall, installs both legitimate advertising programs as well as other, malicious programs.
"Because the Browser Protector software had existed since at least 2011 without exhibiting malicious behavior, many security software vendors had not configured their products to block or remove it," the report stated. "The December release of the MSRT therefore detected and removed it from a large number of computers on which it may have been installed for several months or even years."
The number of remotely exploitable vulnerabilities used by attackers fell to 20 in 2013, down 71 percent from a high of 70 in 2010. In the same time period, exploit kit developers moved from exploiting flaws roughly equally in Microsoft products, Adobe products and Oracle's Java to focusing on Java in more than 70 percent of cases.
The trend shows that attackers have moved their exploitation efforts to software that has less memory protections and defensive mitigations, Microsoft said in the report.
"With new remote code execution vulnerabilities becoming harder to find and exploit as secure coding practices improve across the software industry, the value of previously undisclosed exploits in the underground economy has increased, and developing new exploits has become more expensive," the report stated.
The threat landscape continued to vary by geography. The countries exhibiting the most infections—between 35 and 55 computers cleaned per 1,000—included Martinique, Tunisia, Albania, Pakistan and Yemen. The countries demonstrating the cleanest systems—with only 4 to 10 computers cleaned per 1,000—included Macau, Iceland, Japan, Finland and China, according to the report.