FortiOS 6.2 running AV engine version 6.00142 and below, FortiOS 6.4 running AV engine version 6.00144 and below and FortiClient 6.2 running AV engine version 6.00137 and below may not immediately detect certain types of malformed or non-standard RAR archives, potentially containing malicious files. Based on the samples provided, FortiClient will detect the malicious files upon trying extraction by real-time scanning and FortiGate will detect the malicious archive if Virus Outbreak Prevention is enabled.
Solution:
The product does not implement or incorrectly implements one or more security-relevant checks as specified by the design of a standardized algorithm, protocol, or technique.