Zero-day vulnerability in Windows

Improper input validation
CVE-2017-0143

On April 14, 2017 the Shadow Brokers team made the exploit pack publicly available. The exploits are believed to be stolen from the NSA.

It is unclear, which CVE has been assigned to this vulnerability. Possible CVEs: CVE-2017-0143, CVE-2017-0144, CVE-2017-0145, CVE-2017-0148.

On May 12, 2017 the malicious team has hit over 100,000 organizations in 150 countries. The hackers encrypted files from the target system and demanded 300-600$.

Known malware:

WannaCry (Wana Decryptor) malware (the hackers added .WCRY extention to the targte files). The malware is believed to be connected to Lazarus Group from North Korea.
EternalBlue exploit.

Vulnerability details

Advisory: SB2017031416 - Multiple vulnerabilities in Microsoft Windows SMB Server

Vulnerable component: Windows

CVE-ID: CVE-2017-0143

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-20 - Improper input validation

Description:

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to an error when parsing requests in Microsoft Server Message Block 1.0 (SMBv1) server. A remote unauthenticated attacker can send specially crafted SMB packets and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Public Exploits:

- Microsoft Windows - SrvOs2FeaToNt SMB Remote Code Execution (MS17-010) [Exploit-DB]

- Microsoft Windows - Uncredentialed SMB RCE (MS17-010) (Metasploit) [Exploit-DB]

External links:

https://github.com/misterch0c/shadowbroker/
https://isc.sans.edu/forums/diary/ETERNALBLUE+Windows+SMBv1+Exploit+Patched/22304
https://blogs.technet.microsoft.com/msrc/2017/04/14/protecting-customers-and-evaluating-risk/

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.