Secure SMB Protocol Against Malware | Visuality Systems (2024)

FAQs

Which SMB protocol is secure? ›

Of the 3 major SMB versions, SMB3 — particularly SMB 3.1. 1 — offers the most security. For example, SMB3's secure dialect negotiation limits susceptibility to man-in-the-middle (MITM) attacks and SMB 3.1. 1 uses secure and performant encryption algorithms like AES-128-GCM.

SMB serves as a legitimate means for file sharing and communication between devices in networks. Malware's spread isn't a flaw in the SMB protocol itself; rather, it seizes upon vulnerabilities or credential misuse. The SMB protocol, fundamentally, is secure.

SMB relay attacks exploit SMB's NTLM authentication, potentially allowing attackers to impersonate users and gain unauthorized access. This attack is facilitated by specific prerequisites such as SMB signing disabled on the target, local network access, and user credentials with remote login permissions.

SFTP vs SMB: Speed

But SFTP handles large batches or huge files much more efficiently. SMB performance degrades significantly over high latency networks or the internet due to its “chatty” protocol. SFTP's simpler protocol makes it more resilient to network lag over long distances.

Microsoft has since discontinued the CIFS moniker but continues developing SMB and publishing subsequent specifications. Samba is a free software reimplementation of the SMB protocol and the Microsoft extensions to it.

Smb signatures can be breached by MITM attacks which means your data is compromised. Encryption cannot.

Here's an example of how the SMB works in real life. Let's say that the printer in your office is connected to the office administrator's computer. If you want to print a document, your computer (the client) sends the office administrator's computer (the server) a request to print it and uses the SMB protocol to do it.

We recommend keeping SMBv2 and SMBv3 enabled, but you might find it useful to disable one temporarily for troubleshooting. For more information, see How to detect status, enable, and disable SMB protocols on the SMB Server.

Should I Use CIFS or SMB? The majority of modern storage systems use SMB 2.0, 3.0, or higher. Microsoft strongly recommends users disable CIFS/SMB1 despite compatibility issues this may cause among old devices and software.

What is the disadvantage of SMB? ›

SMB server limitations

The SMB server does not indicate mount points to the SMB client. This can have the effect that SMB clients query free space in the wrong directory, if different filesets are linked to subfolders in an SMB share.

Security concerns

The SMBv1 protocol is not safe to use. By using this old protocol, you lose protections such as pre-authentication integrity, secure dialect negotiation, encryption, disabling insecure guest logins, and improved message signing.

SMB Encryption offers an end-to-end privacy and integrity assurance between the file server and the client. It provides this security regardless of the networks traversed, such as wide area network (WAN) connections maintained by non-Microsoft providers.

I would run a packet capture using Wireshark and see what happens when I read a file – the difference between plain and encrypted SMB packets is easily visible.

Step 1: Open control panel Step 2: Navigate to programs and features. Step 3: Click on "Turn Windows features on or off. Step 4: Disable "(Server Message Block) SMB v1"Step 5 : Click ok.

Version 1.0 of SMB contains a bug that can be used to take over control of a remote computer. The US National Security Agency (NSA) developed an exploit (called “EternalBlue”) for this vulnerability which was subsequently leaked.

A new hashing algorithm, HMAC SHA-256, makes SMB2. 0 more secure compared to the earlier dialects. With SMB3. 0, security has been further enhanced by the AES-CMAC algorithm, and with Windows 11, AES-256-GCM has been introduced.

SMB1 is just old and is not as secure as the latest versions of the SMB protocol. You should be putting a plan in place to remove older devices that still rely on SMB1 (like old photocopiers). This may be easier said than done in some environments.

Security implications of SMB ports

Ports 139 and 445 have been targets for various cyberattacks, including the notorious WannaCry ransomware. These attacks exploit vulnerabilities in the SMB protocol to execute malicious code and spread across networks.