Microsoft Windows Private Communications Transport Protocol Buffer Overrun Vulnerability

Description

Various Microsoft Windows operating systems are prone to a remotely exploitable stack-based buffer overrun via the PCT (Private Communications Transport) protocol. Successful exploitation of this issue could allow a remote attacker to execute malicious code on a vulnerable system, resulting in full system compromise. The vulnerability may also reportedly be exploitable by a local user who passes malicious parameters to the vulnerable component interactively or through another application. This issue is reported to only affect systems that have SSL enabled, such as web servers, but could also affect Windows 2000 Domain Controllers under some circumstances. For Windows Server 2003, PCT must be manually enabled in addition to enabling SSL support to be affected. Reportedly, both PCT 1.0 and SSL 2.0 must be enabled for successful exploitation. The DeepSight Threat Analysis team has observed exploit activity in the wild associated with this vulnerability.

Technologies Affected

• Avaya DefinityOne Media Servers
• Avaya IP600 Media Servers
• Avaya S3400 Message Application Server
• Avaya S8100 Media Servers
• Microsoft Windows 2000 Advanced Server
• Microsoft Windows 2000 Advanced Server SP1
• Microsoft Windows 2000 Advanced Server SP2
• Microsoft Windows 2000 Advanced Server SP3
• Microsoft Windows 2000 Advanced Server SP4
• Microsoft Windows 2000 Datacenter Server
• Microsoft Windows 2000 Datacenter Server SP1
• Microsoft Windows 2000 Datacenter Server SP2
• Microsoft Windows 2000 Datacenter Server SP3
• Microsoft Windows 2000 Datacenter Server SP4
• Microsoft Windows 2000 Professional
• Microsoft Windows 2000 Professional SP1
• Microsoft Windows 2000 Professional SP2
• Microsoft Windows 2000 Professional SP3
• Microsoft Windows 2000 Professional SP4
• Microsoft Windows 2000 Server
• Microsoft Windows 2000 Server SP1
• Microsoft Windows 2000 Server SP2
• Microsoft Windows 2000 Server SP3
• Microsoft Windows 2000 Server SP4
• Microsoft Windows NT Enterprise Server 4.0
• Microsoft Windows NT Enterprise Server 4.0 SP1
• Microsoft Windows NT Enterprise Server 4.0 SP2
• Microsoft Windows NT Enterprise Server 4.0 SP3
• Microsoft Windows NT Enterprise Server 4.0 SP4
• Microsoft Windows NT Enterprise Server 4.0 SP5
• Microsoft Windows NT Enterprise Server 4.0 SP6
• Microsoft Windows NT Enterprise Server 4.0 SP6a
• Microsoft Windows NT Server 4.0
• Microsoft Windows NT Server 4.0 SP1
• Microsoft Windows NT Server 4.0 SP2
• Microsoft Windows NT Server 4.0 SP3
• Microsoft Windows NT Server 4.0 SP4
• Microsoft Windows NT Server 4.0 SP5
• Microsoft Windows NT Server 4.0 SP6
• Microsoft Windows NT Server 4.0 SP6a
• Microsoft Windows NT Terminal Server 4.0
• Microsoft Windows NT Terminal Server 4.0 SP1
• Microsoft Windows NT Terminal Server 4.0 SP2
• Microsoft Windows NT Terminal Server 4.0 SP3
• Microsoft Windows NT Terminal Server 4.0 SP4
• Microsoft Windows NT Terminal Server 4.0 SP5
• Microsoft Windows NT Terminal Server 4.0 SP6
• Microsoft Windows NT Workstation 4.0
• Microsoft Windows NT Workstation 4.0 SP1
• Microsoft Windows NT Workstation 4.0 SP2
• Microsoft Windows NT Workstation 4.0 SP3
• Microsoft Windows NT Workstation 4.0 SP4
• Microsoft Windows NT Workstation 4.0 SP5
• Microsoft Windows NT Workstation 4.0 SP6
• Microsoft Windows NT Workstation 4.0 SP6a
• Microsoft Windows Server 2003 Datacenter Edition
• Microsoft Windows Server 2003 Datacenter Edition Itanium
• Microsoft Windows Server 2003 Enterprise Edition
• Microsoft Windows Server 2003 Enterprise Edition Itanium
• Microsoft Windows Server 2003 Standard Edition
• Microsoft Windows Server 2003 Web Edition
• Microsoft Windows XP 64-bit Edition
• Microsoft Windows XP 64-bit Edition SP1
• Microsoft Windows XP 64-bit Edition Version 2003
• Microsoft Windows XP 64-bit Edition Version 2003 SP1
• Microsoft Windows XP Home
• Microsoft Windows XP Home SP1

Recommendations

Permit local access for trusted individuals only. Where possible, use restricted environments and restricted shells.
Local attack vectors are reported to exist for this vulnerability. Do not permit untrusted individuals to have interactive access to the system. This will reduce exposure to privilege escalation attacks via this or other latent vulnerabilities.

Block external access at the network boundary, unless external parties require service.
Use multiple layers of network access control to regulate external or untrusted network traffic. This will help to limit exposure to exploitation of this and other latent vulnerabilities. This includes blocking RPC ports such as UDP ports 135-139 and 445 and TCP ports 138-139, 445 and 593.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy network intrusion detection systems to monitor network traffic for anomalous or suspicious activity. This may help in detecting attack attempts or activity that is the result of successful exploitation of this or other latent vulnerabilities.

Disable any services that are not needed.
As a precaution, disable SSL-enabled services if they are not explicitly required. This will help to reduce exposure to this issue.

Avaya has released an advisory to announce that Avaya System Products shipping on Microsoft platforms are also affected by this vulnerability. Avaya advise that customers follow the Microsoft recommendations for the resolution of this issue. The aforementioned advisory can be viewed at the following location: http://support.avaya.com/japple/css/japple?temp.groupID=&temp.selectedFamily=128451&temp.selectedProduct=154235&temp.selectedBucket=126655&temp.feedbackState=askForFeedback&temp.documentID=161384&PAGE=avaya.css.CSSLvl1Detail&executeTransaction=avaya.css.UsageUpdate() Microsoft has released fixes to address this issue. US-CERT has released an advisory TA04-104A to address this and other issues. Please see the referenced advisory for more information. Due to the availability of public exploit code and corresponding exploitation in the wild, administrators are strongly advised to apply the available patches or any applicable workarounds and mitigation. June 15, 2004 - Microsoft has updated security bulletin MS04-011 to release a Windows NT 4.0 Workstation update for the Pan Chinese language. The Pan Chinese update should be installed by customers who installed Windows NT 4.0 Workstation for Pan Chinese update or who use the Pan Chinese product.