It's an ongoing challenge for security practitioners: You want to keep all systems up-to-date and secure, but limited resources, legacy systems, and slow patching processes hold you back.

To aid in patch management strategy, researchers with Verint's Cyber Threat Intelligence (CTI) Group analyzed the top 20 vulnerabilities currently exploited by global attack groups. Forty-five percent affect Microsoft products, and some bugs used in successful attacks date back to 2012.

The National Vulnerability Database (NVD) reports 16,514 vulnerabilities were disclosed in 2018, indicating an average of roughly 45 new bugs per day. Additional data shows nearly 60% of all flaws are classified as Critical or High severity, Verint researchers explain in a blog post. Further, 60% of breaches are linked to a bug for which a patch was available but not applied.

Each CVE is given a severity score, though these numbers don't always represent the risk a bug presents. Consider CVE-2018-20250, a WinRAR bug with a CVSS base score of 7.8 in NVD ("High") and 6.8 in CVE Details ("Medium"). Based on its scores, the vulnerability may not merit immediate patching, but Verint points out it has been exploited by at least five APT groups, from different locations, in attacks against the UK, Southeast Asia, Europe, and the Middle East.

Researchers analyzed more than 5,300 feeds and other threat intelligence sources over the past two-and-a-half years, covering at least 800 CVEs. Their list of 20 vulnerabilities to prioritize patching is based on the number of times they have been exploited by advanced threat groups.

Top of the list is CVE-2017-11882, a Microsoft Office memory corruption vulnerability that existed for 17 years before it was patched in November 2017. The flaw exists in Office when the software doesn't properly handle objects in memory; if exploited, it could let an attacker run arbitrary code in the context of the user. A simple phishing attack could do it: Victims would need only to open an infected file with a vulnerable version of Microsoft Word or WordPad.

This flaw was the favorite malware delivery vector in the second and third quarters of 2019. As Verint points out in its writeup, it has also been used in attacks by advanced groups including APT32 (Vietnam), APT34 (Iran), APT40 (China), APT-C-35 (India), Cobalt Group (Spain, Ukraine), Silent Group (Russia), Lotus Blossom (China), Cloud Atlas (Unknown), and FIN7 (Russia).

Second on Verint's list is CVE-2018-8174, a critical vulnerability affecting all versions of Windows. This is a VBScript engine RCE vulnerability that exists in the way VBScript engine handles objects in memory. The bug, dubbed Double Kill, made an appearance in the RIG exploit kit in May 2018. It has been used by Silent Group (Russia) and Dark Hotel (North Korea).

CVE-2017-0199, a critical RCE flaw in the Windows Object Linking and Embedding (OLE) programming interface, is third. The vulnerability, which affects most or all versions of Microsoft Word, had been under attack for months when a patch was released in April 2017. Verint says it has been used by groups including APT34 (Iran), APT40 (China), APT-C-35 (India), Cobalt Group (Spain, Ukraine), APT37 (North Korea), Silent Group (Russia), Gorgon Group (Pakistan), and Gaza Cybergang (Iran).

Fourth is CVE-2018-4878, a critical vulnerability in Adobe Flash Player. The zero-day was being used in active attacks against victims in South Korea when it was reported in February 2018. Later the same month, it appeared in another campaign leveraging malicious Word files. Verint reports the flaw has been used in campaigns by North Korean groups APT37 and Lazarus Group.

CVE-2017-10271, a bug in the Oracle WebLogic Server component of Oracle Fusion Middleware, is listed fifth. The "easily exploitable" vulnerability, as CVE Details describes it, could let an unauthenticated attacker with network access via T3 compromise Oracle WebLogic Server and potentially take over the WebLogic server. This bug has been used by the Rocke Gang, a Chinese criminal group, Verint reports.

Read the full list here.

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