CVE-2018-0243
MediumCVSS 5.8Exploitation Probability (EPSS)
Elevated risk66th percentile - higher than 66% of all known CVEs
Summary
A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a configured file action policy intended to drop SMB2 and SMB3 protocols if malware is detected. The issue is due to incorrect detection of SMB2/SMB3 files based on total file length. An attacker could exploit this by sending a crafted SMB2 or SMB3 transfer request through the targeted device.
Risk Assessment
The organization may be exposed to malware slipping through blocked SMB2/SMB3 protocols, potentially leading to system infections and security breaches.
Recommendation
It is recommended to upgrade Cisco Firepower System Software to version 6.2.3 or later, which includes a fix for this vulnerability.
Original NVD description (English source)
A vulnerability in the detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a configured file action policy that is intended to drop the Server Message Block Version 2 (SMB2) and SMB Version 3 (SMB3) protocols if malware is detected. The vulnerability is due to incorrect detection of an SMB2 or SMB3 file based on the total file length. An attacker could exploit this vulnerability by sending a crafted SMB2 or SMB3 transfer request through the targeted device. An exploit could allow the attacker to pass SMB2 or SMB3 files that could be malware even though the device is configured to block them. This vulnerability does not exist for SMB Version 1 (SMB1) files. This vulnerability affects Cisco Firepower System Software when one or more file action policies are configured, on software releases prior to 6.2.3. Cisco Bug IDs: CSCvg68807.