Using behavior blocking mobility tokens to facilitate distributed worm detection

1. A computer implemented method for tracking movement of suspicious files within a network, the method comprising the steps of:

detecting at a source computer a process on the source computer writing a file to a folder at a target computer;

determining at the source computer a suspicion level associated with the process;

writing by the source computer a first behavior blocking mobility token containing at least the suspicion level associated with the process to the same folder at the target computer;

subsequent to writing the file and the first behavior blocking mobility token to the same folder at the target computer, determining by the source computer whether the process comprises malicious code; and

writing by the source computer a second behavior blocking mobility token to the target computer, the second behavior blocking mobility token informing the target computer whether the process that wrote the file comprises malicious code.

2. The method of claim 1 wherein:

the first behavior blocking mobility token contains at least one datum concerning the source computer from a group of data consisting of:

an IP address;

a computer name; and

a primary domain controller name.

3. The method of claim 1 wherein:

the first behavior blocking mobility token contains at least one datum concerning the process from a group of data consisting of:

a name;

security information;

additional associated suspiciousness information;

an installation time;

an installation source;

data contained in a behavior blocking mobility token associated with the process;

a digital signature;

a version number;

a last modification date; and

a last modification time.

4. The method of claim 1 further comprising:

writing at least one instruction directed to the target computer in the first behavior blocking mobility token.

5. The method of claim 1 further comprising:

writing at least one rule directed to the target computer in the first behavior blocking mobility token.

6. The method of claim 1 wherein the second behavior blocking mobility token is written to the target computer through a named pipe.

7. A computer implemented method for tracking movement of suspicious files within a network, the method comprising the steps of:

detecting a file being written to a folder at a target computer by a source computer;

detecting that a first behavior blocking mobility token associated with the file is being written to the same folder at the target computer by the source computer;

reading the first behavior blocking mobility token;

determining a suspicion level of the file associated with the first behavior blocking mobility token, responsive to contents of the behavior blocking mobility token; and

subsequent to detecting the file and the first behavior blocking mobility token being written to the same folder at the target computer, detecting a second behavior blocking mobility token being written to the target computer, the second behavior blocking mobility token indicating whether the file was written to the target computer by malicious code on the source computer, wherein the source computer determines whether the file was written to the target computer by malicious code and writes the second behavior blocking mobility token to the target computer.

8. The method of claim 7 further comprising:

reading at least one instruction from the source computer in the first behavior blocking mobility token; and

executing the at least one instruction.

9. The method of claim 7 further comprising:

reading at least one rule from the source computer in the first behavior blocking mobility token; and

processing the file associated with the first behavior blocking mobility token responsive to the at least one rule.

10. The method of claim 7 further comprising:

processing the file associated with the first behavior blocking mobility token responsive to at least one rule originating at the target computer.

11. The method of claim 7 further comprising:

in response to at least the suspicion level, treating the file associated with the first behavior blocking mobility token as being suspicious.

12. The method of claim 7 further comprising:

in response to at least the suspicion level, rejecting the file associated with the first behavior blocking mobility token.

13. The method of claim 7 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by malicious code, treating the associated file as malicious code.

14. The method of claim 7 wherein the second behavior mobility token is written to the target computer through a named pipe.

15. The method of claim 7 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by legitimate code, treating the associated file as legitimate code.

16. The method of claim 7 further comprising:

responsive to not receiving communication from the source computer for a specified period of time, raising the suspicion level of the associated file.

17. A computer readable storage medium containing an executable computer program product for tracking movement of suspicious files within a network, the computer program product comprising:

program code for detecting at a source computer a process on the source computer writing a file to a folder at a target computer;

program code for determining at the source computer a suspicion level associated with the process;

program code for writing by the source computer a first behavior blocking mobility token containing at least the suspicion level associated with the process to the same folder at the target computer;

program code for determining by the source computer whether the process comprises malicious code subsequent to writing the file and the first behavior blocking mobility token to the same folder at the target computer; and

program code for writing by the source computer a second behavior blocking mobility token to the target computer, the second behavior blocking mobility token informing the target computer whether the process that wrote the file comprises malicious code.

18. The computer program product of claim 17 further comprising:

program code for writing at least one instruction directed to the target computer in the first behavior blocking mobility token.

19. The computer program product of claim 17 further comprising:

program code for writing at least one rule directed to the target computer in the first behavior blocking mobility token.

20. A computer readable storage medium containing an executable computer program product for tracking movement of suspicious files within a network, the computer program product comprising:

program code for detecting a file being written to a folder at a target computer by a source computer;

program code for detecting that a first behavior blocking mobility token associated with the file is being written to the same folder at the target computer by the source computer;

program code for reading the first behavior blocking mobility token;

program code for determining a suspicion level of the file associated with the first behavior blocking mobility token, responsive to contents of the behavior blocking mobility token; and

program code for detecting a second behavior blocking mobility token being written to the target computer subsequent to detecting the file and the first behavior blocking mobility token being written to the same folder at the target computer, the second behavior blocking mobility token indicating whether the file was written to the target computer by malicious code on the source computer, wherein the source computer determines whether the file was written to the target computer by malicious code and writes the second behavior blocking mobility token to the target computer.

21. The computer program product of claim 20 further comprising:

program code for reading at least one instruction from the source computer in the first behavior blocking mobility token; and

program code for executing the at least one instruction.

22. The computer program product of claim 20 further comprising:

program code for reading at least one rule from the source computer in the first behavior blocking mobility token; and

program code for processing the file associated with the first behavior blocking mobility token responsive to the at least one rule.

23. The computer program product of claim 20 further comprising:

program code for processing the file associated with the behavior blocking mobility token responsive to at least one rule originating at the target computer.

24. The computer program product of claim 20 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by malicious code, treating the associated file as malicious code.

25. The computer program product of claim 20 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by legitimate code, program code for treating the associated file as legitimate code.

26. A computer system having a computer-readable storage medium having executable computer program instructions embodied therein for tracking movement of suspicious files within a network, the computer system computer program instructions comprising:

a software portion configured to detect at a source computer a process on the source computer writing a file to a folder at a target computer;

a software portion configured to determine at the source computer a suspicion level associated with the process;

a software portion configured to write by the source computer a first behavior blocking mobility token containing at least the suspicion level associated with the process to the same folder at the target computer;

a software portion configured to determine by the source computer whether the process comprises malicious code subsequent to writing the file and the first behavior blocking mobility token to the same folder at the target computer; and

a software portion configured to write by the source computer a second behavior blocking mobility token to the target computer, the second behavior blocking mobility token informing the target computer whether the process that wrote the file comprises malicious code.

27. The computer system of claim 26 further comprising:

a software portion configured to write at least one instruction directed to the target computer in the first behavior blocking mobility token.

28. The computer system of claim 26 further comprising:

a software portion configured to write at least one rule directed to the target computer in the first behavior blocking mobility token.

29. A computer system having a computer-readable storage medium having executable computer program instructions embodied therein for tracking movement of suspicious files within a network, the computer program instructions comprising:

a software portion configured to detect a file being written to a folder at a target computer by a source computer;

a software portion configured to detect that a first behavior blocking mobility token associated with the file is being written to the same folder at the target computer by the source computer;

a software portion configured to read the first behavior blocking mobility token;

a software portion configured to determine a suspicion level of the file associated with the first behavior blocking mobility token, responsive to contents of the behavior blocking mobility token; and

a software portion configured to detect a second behavior blocking mobility token being written to the target computer subsequent to detecting the file and the first behavior blocking mobility token being written to the same folder at the target computer, the second behavior blocking mobility token indicating whether the file was written to the target computer by malicious code on the source computer, wherein the source computer determines whether the file was written to the target computer by malicious code and writes the second behavior blocking mobility token to the target computer.

30. The computer system of claim 29 further comprising:

a software portion configured to read at least one instruction from the source computer in the first behavior blocking mobility token; and

a software portion configured to execute the at least one instruction.

31. The computer system of claim 29 further comprising:

a software portion configured to read at least one rule from the source computer in the first behavior blocking mobility token; and

a software portion configured to process the file associated with the first behavior blocking mobility token responsive to the at least one rule.

32. The computer system of claim 29 further comprising:

a software portion configured to process the file associated with the first behavior blocking mobility token responsive to at least one rule originating at the target computer.

33. The computer system of claim 29 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by malicious code, a software portion configured to treat the associated file as malicious code.

34. The computer system of claim 29 further comprising:

responsive to the second behavior mobility token indicating that the file was written to the target computer by legitimate code, a software portion configured to treat the associated file as legitimate code.