Executive brief
A vulnerability in older Microsoft Windows operating systems allows a remote attacker to crash a computer by sending a specifically crafted network packet. This attack, historically known as 'WinNuke', targets the system's networking components and results in a 'Blue Screen of Death,' causing immediate service disruption and potential data loss for unsaved work. It does not allow the attacker to steal data, but it can be used to repeatedly take systems offline.
Technical details
The vulnerability is a denial of service (DoS) caused by the incorrect handling of TCP 'out-of-band' (OOB) data by the Windows networking stack. An attacker can trigger the flaw by sending a TCP packet with the URG (Urgent) flag set to port 139 (NetBIOS). When the operating system receives this unexpected OOB data on the NetBIOS session, it fails to process it correctly, leading to a kernel panic and a Blue Screen of Death (BSOD). This is a network-based attack that requires no authentication and no user interaction. Microsoft released patches for this issue shortly after its discovery in 1997.
Affected products
- Microsoft Windows 95
- Microsoft Windows NT
Timeline
- 1997-07-01: disclosed: Initial publication of the vulnerability.