Protection Against the Server Message Block (SMB) Vulnerability Exploit | Paladion

Balaji V
By Balaji V

August 22, 2019

Get Protection for Server Message Block (SMB) Vulnerability

SMB Vulnerability and Protection

What is SMB and why does it matter? An SMB exploit is a fairly common cyberattack. Theacronym SMB stands for Server Message Block, and it is a network protocol for communications on a Windows-based system. A network protocol includes all of the procedures and formats used for communicating over a network, and the protocol controls the process of sending secure data over a network. SMB also controls authentication, printing over the network, and file sharing. The SMB protocol performs this function for Windows based networks. But in older Windows systems, there are vulnerabilities that give hackers the ability to insert malware into systems and spread it quickly. Read on to learn more about SMB vulnerabilities and how you can protect yourself from an
SMB exploit.

What is an SMB vulnerability?

In Windows systems before Windows 10, there are vulnerabilities in the network protocol. An SMB vulnerability is an easy spot for hackers to find access to a system and insert malware. There are currently three known exploits for
these vulnerabilities.

One of the vulnerabilities on an SMB server is found in a spot that allows for buffer overflow, and the hackers exploit this overflow to give them the ability to control content in some memory locations. Another vulnerability is with the file sharing firewall that doesn’t verify the type of code being entered before allowing it in, which gives hackers the opportunity to put their malware in from any location with remote code. The final known vulnerability is with how SMB handles transactions. The system relies on a stable order of events, so a bug occurs when the system doesn’t go in the right order, and this allows hackers inside the system.

How does an SMB attack work?

SMB attacks are the best known remote code execution attacks for Windows systems, and because it is a remote code attack, the hackers can be anywhere. They just need to gain a foothold in a system from the vulnerabilities, exploit that, run commands on the system, place malware, and the attack is underway. The advantage of an SMB attack is that hackers are able to expand their access through systems laterally. Unpatched Windows systems can be infected when they connect to an infected system, and the attack requires less work for a large payout, which is why SMB attacks are so common.

Examples of SMB attacks

The most famous SMB attack is WannaCry. This attack exploited the overflow vulnerability with the EternalBlue exploit and persisted worldwide in systems for a year and a half. Another example of the EternalBlue exploit is Emotet, which targets banks. Other SMB exploits include EternalRomance, used for NotPetya and Bad Rabbit, and EternalEnergy. There is the possibility of a fourth exploit called EternalSynergy, but nothing has appeared in a while.

SMB Vulnerability Protection

The best protection from an SMB attack is to patch your system. A patched system will prevent attackers from gaining access, but a large amount of Windows systems still haven’t been patched. Microsoft has provided the March 2017 update, which can help patch the Server Message Block vulnerabilities, and using this patch is one of the best ways to protect a system. If your Windows system is Windows 10 or later, then the update patches are already built in, which is why most SMB attacks target Windows 7 and earlier. In addition, the WannaCry patch can block EternalBlue exploits, and can block similar vulnerabilities. These patches are some of the best SMB server security methods possible.

As with most protection from cyberattacks, it is best to have layers of security. Aside from the Wannacry patch and ransomware patch, protect your systems further by blocking SMB access from the internet, blocking SMB in offsite computers when in public places, and disabling SMB if not required for a computer. These simple steps can provide further system security from
SMB exploits.

Finally, using vulnerability scanning and Managed Detection and Response services can prevent and detect SMB attacks and other cyberattacks in
your system.

Tags: PCI compliance and SIEM, Uncategorized


Balaji V