For more than a month , at least ten groups of attackers have been compromising systems running applications built with Apache Struts and installing backdoors , DDoS bots , cryptocurrency miners , or ransomware , depending if the machine is running Linux or Windows . For their attacks , the groups are using a zero-day in Apache Struts , disclosed Vulnerability-related.DiscoverVulnerability and immediately fixed Vulnerability-related.PatchVulnerability last month by Apache . The vulnerability , CVE-2017-5638 , allows an attacker to execute commands on the server via content uploaded to the Jakarta Multipart parser component , deployed in some Struts installations . Attackers initially focused on Linux server . According to cyber-security firms F5 , attacks started as soon as Cisco Talos researchers revealed Vulnerability-related.DiscoverVulnerability the zero-day 's presence and several proof-of-concept exploits were published Vulnerability-related.DiscoverVulnerability online . Since early March , attacks have slowly evolved . F5 experts say that in the beginning , attackers targeted Struts instances running on Linux servers , where they would end up installing the PowerBot malware , an IRC-controlled DDoS bot also known as PerlBot or Shellbot . In later attacks , some groups switched to installing a cryptocurrency miner called `` minerd '' that mined for the Monero cryptocurrency . In other attacks reported by the SANS Technology Institute , some attackers installed Perl backdoors . Recent attacks also targeted Struts running on Windows Both SANS and F5 experts report that after March 20 , one of these groups switched to targeting Struts instances installed on Windows systems . Using a slightly modified exploit code , attackers executed various shell commands to run the BITSAdmin utility and then downloaded ( via Windows ' built-in FTP support ) the Cerber ransomware . From this point on , Cerber took over , encrypted files , and displayed its standard ransom note , leaving victims no choice but pay the ransom demand Attack.Ransom or recover data from backups . `` The attackers running this [ Cerber ] campaign are using the same Bitcoin ID for a number of campaigns , '' the F5 team said . `` This particular account has processed 84 bitcoins [ ~ $ 100,000 ] . '' F5 experts also noted that , on average , roughly 2.2 Bitcoin ( ~ $ 2,600 ) go in and out of this particular wallet on a daily basis . The most recent payments dates to today . It is worth mentioning that F5 published their findings last week , on March 29 . Today , SANS detailed similar findings , meaning the campaign spreading Cerber ransomware via Struts on Windows is still going strong . A patch for Apache Struts servers is available Vulnerability-related.PatchVulnerability on the Struts website . Struts is an open source MVC framework for creating modern Java web applications , and its widely used in enterprise environments , for both Intranets and public websites . Some of the initial attacks on Struts-based applications have been tracked by cyber-security firm AlienVault .