This attack could pose a serious security threat. You should take immediate action to stop any damage or prevent further damage from happening.
This signature detects attempts to download exploits from a malicious toolkit which may compromise a computer through various vendor vulnerabilities.
Malicious toolkits contain various exploits bundled into a single package. Victims visiting the malicious server hosting exploit toolkit is attacked with several different exploits exploiting different vulnerabilities one by one. Exploits may include malicious PDF files and java applets.