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 Digital Certificates used by malwares when communicating with Command and Control servers or Digital Certificates used in MITM attacks.
Digital Certificates are sometimes used by malwares to encrypt their communications with the Command and Control servers. Attackers can also leverage these Digital Certificates to spoof content, phishing or man-in-the-middle attacks against all Web browser users.