Persistent malware detection is a sign of bad security practices. It could be caused by one or more of the following reasons:
- Anti-virus software is not properly configured
- There’s an infected computer with no anti-virus software
- Vulnerable operating system or application
- Weak passwords
- Open network share
- Unsecure configuration of the operating system, services, or applications
If persistent malware detection occurs after managing outbreaks in OfficeScan, follow the recommendations below:
Apply the recommended settings
Applying the recommended settings offers the best protection against malware. Please refer to the KB article on the best practices in configuring OfficeScan for malware protection.
Identify and clean the infection sources
- Export the virus/malware Logs.
- From the logs, check for infection sources under the Infection Source column.
- Clean the infection sources using ATTK and ensure that they have OfficeScan Agent installed. Should you need additional recommendation, submit the Virus/Malware Logs to Trend Micro Technical Support for analysis.
Check for Unmanaged Endpoints
Machines that do not have antivirus software installed are prone to infection. They could potentially compromise other machines in the network.
The Unmanaged Endpoints in OfficeScan can be found under Assessment > Unmanaged Endpoints. It can display machines with the following status:
- Managed by another OfficeScan server
- No OfficeScan agent installed
- Unreachable
- Unresolved Active Directory assessment
Run a regular security assessment to check for Unmanaged Endpoints and install OfficeScan agent on unprotected machines.
Implement continuous vulnerability management
Threat actors take advantage of vulnerabilities to deploy an attack. A good example is the WannaCry ransomware which leverages the vulnerability in SMBv1. Organizations who do not proactively scan for vulnerabilities and patch them are at risk of having their network compromised.
Consider changing your password
Some malware use dictionary or brute force attack to gain access to administrative shares. Should you encounter a persistent malware detection, check the Threat Encyclopedia or other online resources and verify if the malware has the ability to do the aforementioned. If yes, then immediately change your password.
Use passphrases instead of passwords. Passphrases are easier to remember and harder to crack compared to complex passwords. Refer to NIST’s article on Easy Ways to Build a Better P@$5w0rd.
General Recommendation
- Open network shares can disclose sensitive information about an organization. It can also be an channel for malware to propagate. Find open network shares before malware or someone else does. There are many free tools available online such as Sysinternals ShareEnum.
- Harden the operating system, applications, and services. Refer to the latest benchmarks available online like CIS Benchmarks.
- Implement the Principle of Least Privilege. Users should only have the permissions necessary to perform their work. If a privileged user has been compromised, then the attacker can execute operations in the context of that user and take over the system.
