KLA10977
Multiple vulnerabilities in Microsoft Server Message Block (SMB)

Multiple serious vulnerabilities have been found in Microsoft Server Message Block 1.0(SMBv1). Malicious users can exploit these vulnerabilities to execute arbitrary code or obtain sensitive information.

Below is a complete list of vulnerabilities:

1. An improper handling of certain requests can be exploited remotely by an unauthenticated attacker via specially designed packets to execute code on the target server;
2. An improper handling of certain requests can be exploited remotely by an unauthenticated attacker via specially designed packets to execute code to obtain sensitive information from the server.

Technical details

Successful exploitation of these vulnerabilities can trigger WannaCry attack.

In case of WannaCry attack, EternalBlue modules are used to begin exploiting SMB vulnerabilities; if an attempt of exploit is successful, the DoblePulsar backdoor is used to install the malware.

Both SMBv1 and SMBv2 packets can be used in WannaCry attack, so disabling them can prevent the operational system from being infected. It is highly recommended to disable SMBv1, because this old protocol doesn’t have any significant impacts on modern operational systems. Disabling SMBv2 can cause serious problems.

For more details see Securelist article.

Users of Windows XP, Windows 8 and Windows server 2003 should read Customer Guidance for WannaCrypt attacks from Microsoft.

Note that Windows 10 and Windows Server 2016 are not affected by the WannaCry attack.

Microsoft Windows XP Service Pack 2
Microsoft Windows XP Service Pack 3
Microsoft Windows XP Embedded Service Pack 3
Microsoft Windows Vista Service Pack 2
Microsoft Windows 7 Service Pack 1
Microsoft Windows 8
Microsoft Windows 8.1
Microsoft Windows RT 8.1
Microsoft Windows 10
Microsoft Windows Server 2003 Service Pack 2 
Microsoft Windows Server 2008 Service Pack 2
Microsoft Windows Server 2008 R2 Service Pack 1
Microsoft Windows Server 2012
Microsoft Windows Server 2012 R2
Microsoft Windows Server 2016

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)