Researchers have detected multiple instances of cyberattackers using SharePoint vulnerability CVE-2019-0604 to target government organizations in the Middle East. These mark the latest cases of adversaries exploiting the flaw, which was recently used to breach the United Nations.
CVE-2019-0604 exists when SharePoint fails to check the source markup of an application package. Attackers could exploit this by uploading a specially crafted SharePoint application package to an affected version of the software. If successful, they could run arbitrary code in the context of both the SharePoint application pool and the SharePoint server farm account.
Microsoft released a patch for the vulnerability in February 2019 and later updated its fix in April. Shortly after, reports surfaced indicating the remote code execution flaw was under active attack. A series of incidents used the China Chopper web shell to gain entry into a target; evidence shows attackers used the web shell to gain network access at several organizations.