The recent RPC attacks on Microsoft Windows® Systems have also revealed a denial of service vulnerability in the OSF DCE code base.

The exploit tools for CERT vulnerabilities VU#568148 and VU#326746 that are now being used widely throughout the internet seek out systems that support the RPC endpoint map service on port 135 and attempt to attack those systems. Since OSF RPC and MS RPC provide similar functionality on port 135, the exploits attempt to attack both types of systems.

The Entegrity implementations of DCE RPC are NOT vulnerable to the DCOM buffer overflow attacks described in CERT VU#568148, however, the exploit tools DO cause an error path to be executed that results in a NULL pointer dereference and a subsequent service termination, resulting in a denial of service. This vulnerability has been reported to CERT, and has been assigned VU#377804.

The repair for this vulnerability requires that users install a new version of the DCE client runtime library. This patch should be applied to all systems that run DCE. Entegrity has created patches for all of its currently supported versions.

Note for Tru64 Users

A patch was issued on 07-Aug-2003 that fixed the original vulnerability, but later a security issue was found with Entegrity DCE versions 4.2 and 4.3 ONLY.

Obtaining the Patch

To obtain the patch, click here.

Applying the Patch

For Linux systems:

1. If you are running DFS, stop DFS.
2. Stop DCE.
3. Unzip and untar the file you downloaded.
4. Replace /opt/dcelocal/usr/lib/libdce.so.1.0.1 with the file you unzipped and untarred.
5. Reboot.

For Windows (PC-DCE) systems:

1. Download the patch.
     
   
2. Unzip the patch file.
     
   
3. Double-click the file you just unzipped. PC-DCE will be automatically updated. When the update finishes, a message will appear indicating the update was successful.
     
   
4. Reboot the machine. The update does not take effect until the machine has been rebooted.

   Note: When the cell comes back up, it may take a minute or two for the daemons to resynchronize themselves with the master. Initially, the PC-DCE Service Panel may say the daemons are unavailable. After about one minute, click Refresh and the servers will run normally.

For Tru64 systems EXCEPT those running Entegrity DCE or DFS versions 4.2 and 4.3:

1. Stop DCE.
2. Copy libdce.so_patch_file file to /opt/dcelocal/shlib
3. Rename /opt/dcelocal/shlib/libdce.so_patch_file to /opt/dcelocal/shlib/libdce.so
4. Issue the following command:
      chmod 644 libdce.so
5. Start DCE.

For Tru64 systems running Entegrity DCE or DFS versions 4.2 and 4.3, click here.