Microsoft Windows POSIX Subsystem Buffer Overflow Local Privilege Escalation Vulnerability



Date Discovered

July 13, 2004


The Microsoft POSIX subsystem implementation is prone to a local buffer overflow vulnerability. A local attacker may exploit this vulnerability in order to run code with elevated privileges, fully compromising the vulnerable computer.

Technologies Affected

  • Avaya S3400 Message Application Server
  • Microsoft Interix 2.2
  • Microsoft Windows 2000 Advanced Server SP2
  • Microsoft Windows 2000 Advanced Server SP3
  • Microsoft Windows 2000 Advanced Server SP4
  • Microsoft Windows 2000 Datacenter Server SP2
  • Microsoft Windows 2000 Datacenter Server SP3
  • Microsoft Windows 2000 Datacenter Server SP4
  • Microsoft Windows 2000 Professional SP2
  • Microsoft Windows 2000 Professional SP3
  • Microsoft Windows 2000 Professional SP4
  • Microsoft Windows 2000 Server SP2
  • Microsoft Windows 2000 Server SP3
  • Microsoft Windows 2000 Server SP4
  • Microsoft Windows NT 4.0 SP6 alpha
  • Microsoft Windows NT Enterprise Server 4.0 SP6a
  • Microsoft Windows NT Server 4.0 SP6a
  • Microsoft Windows NT Terminal Server 4.0 SP6
  • Microsoft Windows NT Workstation 4.0 SP6a


Permit local access for trusted individuals only. Where possible, use restricted environments and restricted shells.
An attacker will require local interactive access prior to being in a position to exploit this vulnerability. Permit local interactive access for trusted users only.

Microsoft has released an updated security bulletin (MS04-020) and fixes to address this issue for supported operating systems. Avaya has released an advisory that acknowledges this vulnerability for Avaya products. Avaya advise that customers follow the Microsoft recommendations to address this issue. Please see the referenced Avaya advisory at the following location for further details:



Discovery of this vulnerability is credited to Rafal Wojtczuk of Network Associates.

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