W32/Blaster worm taking advantage of "Buffer Overrun In RPC Interface " and Denial of Service.
Impact
A remote attacker could exploit these vulnerabilities and execute arbitrary code with Local System privileges or to cause denial-of-service DoS condition.
Apply patches
All users are encouraged to apply the patches referred to in Microsoft Security Bulletin MS03-026 as soon as possible in order to mitigate the vulnerability. These patches are also available via Microsoft's Windows Update service.
Systems running Windows 2000 may still be vulnerable to at least a denial-of-service attack if their DCOM RPC service is available via the network. Therefore, sites are encouraged to use the packet filtering tips below in addition to applying the patches supplied in MS03-026.
It has been reported that some affected machines are not able to stay connected to the network long enough to download patches from Microsoft. For hosts in this situation, below mentioned steps should be taken
1. Physically disconnected the system from network.
2. Check the system for signs of compromise.
In most cases, an infection will be indicated by the presence of the registry key "HKEY_LOCAL_MACHINE\ SOFTWARE\Microsoft \Windows\ CurrentVersion \Run\windows auto update" with a value of msblast.exe. If this key is present, remove it using a registry editor.
3. If the machine is infected, terminate the running copy of msblast.exe using the Task Manager.
4. Search for and delete files named msblast.exe
5. Take one of the following steps to protect against the compromise prior to installing the Microsoft patch:
Disable DCOM as described in MS03-026
Enable Microsoft's Internet Connection Filter ICF , or another host-level packet filtering program to block incoming connections for 135/tcp
6. The system may be reconnected to the network and apply the patches in the recommended manner
Anti-virus vendors have also published steps to recover from mentioned worm infection, links are provided in references.
Disable DCOM
Depending on site requirements, user may wish to disable DCOM as described in MS03-026. Disabling DCOM will help protect against this vulnerability but may also cause undesirable side effects. Additional details on disabling DCOM and possible side effects are available in Microsoft Knowledge Base Article 825750.
Filter network traffic
Sites should consider blocking both inbound and outbound traffic to the below mentioned ports, depending on network requirements, at the host and network level. Microsoft's Internet Connection Firewall can be used to accomplish these goals.
69 UDP
135 TCP
135 UDP
139 TCP
139 UDP
445 TCP
445 UDP
4444 TCP
The current exploits for VU#568148 create a backdoor, which is in some cases 4444/TCP, blocking inbound TCP sessions to ports on which no legitimate services are provided may limit intruder access to compromised hosts.
The information provided herein is on "as is" basis, without warranty of any kind.