WebShell

Cases of Attacks Targeting Vulnerable Atlassian Confluence Servers

The ASEC analysis team has been monitoring attacks that are targeting vulnerable systems. This post will discuss cases of attacks targeting vulnerable Atlassian Confluence Servers that are not patched. Atlassian’s Confluence is a major collaboration platform used by many companies across the globe. Being a web-based platform, services such as managing projects and collaboration are mainly provided by Confluence Servers (or Confluence Data Centers). As it is a solution used by many companies, many vulnerabilities targeting vulnerable Confluence Servers and…

Meterpreter Distributed to Vulnerable Server of Korean Medical Institution

While monitoring malware strains distributed to vulnerable servers, the ASEC analysis team discovered an attack case for PACS (Picture Archiving and Communication System) server used by Korean medical institutions. PACS is a system for digitally managing and transferring medical images of patients, which is used to check and interpret the images without being restrained by time and space. This system is thus used by many hospitals. As there are multiple PACS vendors, each medical institution may use different PACS systems….

PHP WebShell Malware using Image Files

WebShell is a file that is uploaded to a web server which runs file navigation or system shell commands. The attacker can use the web browser to navigate through the files of the server system and issue shell commands. Certain file extensions for uploaded files can be restricted to prevent malicious WebShell files from being uploaded to the server; however, the attacker can bypass such actions with the following method: Upload a file that bypasses the Server-Side Script’s file extension…