Active e-mail filter with challenge-response

• US 20040015554A1
• Filed: 07/16/2002
• Published: 01/22/2004
• Est. Priority Date: 07/16/2002
• Status: Active Grant

• Current Assignee: Quest Software, Inc.
• Original Assignee: Dell Software, Inc. (Dell Technologies Inc.)
• Inventors: Wilson, Brian
• Granted Patent: US 8,924,484 B2
• Time in Patent Office: Days
• US Class Current: 709/206
• CPC Class Codes: G06Q 10/107 Computer-aided management of electronic mailing [e-mailing]
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 51/42 Mailbox-related aspects, e.g. synchronisation of mailboxes

Abstract

When a user receives potential junk e-mail from an unknown sender address, an active filter installed in or cooperating with the user'"'"'s e-mail system sends a challenge e-mail back to the sender address. Unless the user receives a correct response e-mail from the sender address and/or a response that meets formal criteria, the active filter rejects the original e-mail and blocks future e-mail from that sender address. The challenge preferably includes a question that the sender must correctly answer in his response. The question is such that only humans can interpret and respond to it correctly. For example, the question may relate to and/or be incorporated in an image in the challenge. Lists of approved and blocked sender addresses are compiled. The user may directly enter addresses in the address lists. Addresses to which the user has sent e-mail may also be included directly in the approved list.

Claims

1. A method for filtering electronic mail (e-mail) sent to a user comprising:

receiving a current e-mail message from a sender address;

via e-mail, returning to the sender address a challenge that requires a correct e-mail response; and

blocking the current e-mail message from the sender address unless the correct e-mail response is received by the user system from the sender address.

2. A method as in claim 1, further including the step of blocking future e-mail messages from the sender address unless the correct e-mail response is received by the user from the sender address.

3. A method as in claim 1, in which the challenge includes an instruction to perform an action, the correct e-mail response requiring correct performance of the action.

4. A method as in claim 3 including the sub-step of including a question in the challenge, in which the action is answering the question.

5. A method as in claim 3 further comprising the sub-step of including an image in the challenge.

6. A method as in claim 5 including the sub-step of incorporating a legible question as part of the image, in which the action is answering the question.

7. A method as in claim 5 further comprising the sub-step of including in the challenge, in a text format, a question about the image, in which the action is answering the question.

8. A method as in claim 3, further comprising user selection of the challenge.

9. A method as in claim 3 further comprising the sub-step of including an audio file in the challenge.

10. A method as in claim 3 further comprising downloading challenges via a network from an external challenge-generation system and selecting for sending to the sender address at least one of the downloaded challenges.

11. A method as in claim 3, further including the step of blocking the current e-mail message from the sender address unless the correct e-mail response is received according to a formal response criterion.

12. A method as in claim 11, in which the formal response criterion is receipt by the user from the sender address of an e-mail response within a response period.

13. A method as in claim 11, further comprising allowing multiple attempts to return a correct e-mail response from the sender address by submitting at least one additional challenge to the sender address upon receipt of an incorrect e-mail response from the sender address.

14. A method as in claim 13, in which the formal response criterion is receipt by the user from the sender address of the correct e-mail response within at most a predetermined maximum number of the multiple attempts.

15. A method as in claim 3 further comprising the following steps:

upon receipt of the correct e-mail response from the sender address, including the sender address in a list of approved sender addresses and accepting the current e-mail message; and

accepting without challenge any e-mail message sent from an address included in the list of approved sender addresses.

16. A method as in claim 15, further comprising the step of including user-specified e-mail addresses in the list of approved sender addresses.

17. A method as in claim 15, further comprising the step of including in the list of approved sender addresses any e-mail address to which the user has initiated sending an e-mail message.

18. A method as in claim 15, further comprising the step of including in the list of approved sender addresses e-mail addresses obtained from an externally compiled address list.

19. A method as in claim 3 further comprising the following steps:

unless the correct e-mail response is received from the sender address, including the sender address in a list of blocked sender addresses; and

blocking without further challenge any e-mail message received from any address included in the list of blocked sender addresses.

20. A method as in claim 19, further comprising the step of including user-specified e-mail addresses in the list of blocked sender addresses.

21. A method as in claim 19, further comprising the step of including e-mail addresses obtained from an externally compiled address list in the list of blocked sender addresses.

22. A method as in claim 19, further comprising the step of including the sender address in the list of blocked sender addresses unless the correct e-mail response is received according to a formal response criterion.

23. A method as in claim 19, further comprising the step of providing the list of blocked addresses to third parties.

24. A method as in claim 3 further comprising the following steps:

notifying the user of receipt of the current e-mail message and prompting to indicate whether to send the challenge; and

sending the challenge only if the user indicates that the challenge should be sent.

25. A method as in claim 1 further including the steps of calculating, for each challenge, a corresponding key, and including the key in the challenge.

26. A method as in claim 25 further including the step of accepting for display to the user, without challenge, any incoming message that contains a correctly calculated key.

27. A method as in claim 25 further including the step of accepting for display to the user, without challenge, any incoming message that both contains a correctly calculated key and is sent from a sender address to which the user previously initiated sending a message.

28. A method for filtering electronic mail (e-mail) sent to a user comprising:

receiving a current e-mail message from a current sender address;

via e-mail, returning to the current sender address a challenge that requires a correct e-mail response, the challenge including an instruction to perform an action and the correct e-mail response requiring correct performance of the action;

if the correct e-mail response is received from the current sender address, including the current sender address in a list of approved sender addresses and accepting without challenge the current e-mail message and any e-mail message sent from an address included in the list of approved sender addresses; and

if the correct e-mail response is not received from the current sender address, including the current sender address in a list of blocked sender addresses and blocking without further challenge any e-mail message received from any address included in the list of blocked sender addresses, including the current e-mail message.

29. A system for filtering electronic mail (e-mail) sent to a user comprising:

a computer that is connected to a network over which e-mail is transmitted;

a computer program executing on the computer, wherein the computer program comprises computer instructions for;

receiving a current e-mail message from a sender address to a user address;

via e-mail, returning to the sender address a challenge that requires a correct e-mail response; and

blocking the current e-mail message from the sender address unless the correct e-mail response is received by the computer from the sender address.

30. A system as in claim 29, in which the computer program further comprises computer instructions for generating the challenge to include an instruction to perform an action, the correct e-mail response requiring correct performance of the action.

31. A system as in claim 30, further comprising an approved list storing approved sender addresses, in which the computer program further comprises computer instructions for:

including the sender address in a list of approved sender addresses and for accepting the current e-mail message upon receipt of the correct e-mail response from the sender address; and

accepting without challenge any e-mail message sent from an address included in the list of approved sender addresses.

32. A system as in claim 30, further comprising a blocked list storing disapproved sender addresses, in which the computer program further comprises computer instructions for:

including the sender address in a list of blocked sender addresses unless the correct e-mail response is received from the sender; and

blocking without further challenge any e-mail message received from any address included in the list of blocked sender addresses.

33. A system as in claim 29, further comprising a challenge generation module generating the challenge to include an instruction to perform an action, the correct e-mail response requiring correct performance of the action.

34. A system as in claim 33, further comprising a response analysis module analyzing any e-mail response from the sender address and determining whether the e-mail response is correct.

35. A system as in claim 33, in which the challenge generation module is provided for downloading challenges via the network from an external challenge-generation system and selecting for sending to the sender address at least one of the downloaded challenges.