Quarantining electronic messages based on relationships among associated addresses

1. A method comprising:

determining relationships between a first plurality of electronic message addresses associated with a first domain and a second plurality of electronic message addresses associated with a second domain, wherein determining the relationships between the first plurality of electronic message addresses associated with the first domain and the second plurality of electronic message addresses associated with the second domain comprises:

identifying a one-way communication between the first plurality of electronic message addresses and the second plurality of electronic message addresses;

assigning a first weight to the one-way communication;

identifying two-way communications between a first given message address of the first plurality of electronic message addresses and a second given message address of the second plurality of electronic message addresses; and

assigning a second weight to the two way communications based on a number-based criterion for the two-way communications such that the number-based criterion causes the second weight to correspond to a relatively higher strength for the two-way communications for a relatively larger number of the two-way communications and causes the second weight to correspond to a relatively lower strength for the two-way communications for a relatively smaller number of the two-way communications;

determining a relationship between the first domain and the second domain based on the first weight and the second weight; and

quarantining an electronic message originating from a sender associated with the first domain in response to the relationship between the first domain and the second domain meeting a second criterion.

2. The method of claim 1 , wherein the electronic message is associated with an electronic message address of the first plurality of electronic message addresses.

3. The method of claim 1 , wherein quarantining the electronic message comprises:

isolating an attachment associated with the electronic message in a sand box; and

analyzing the attachment in the sand box.

4. The method of claim 1 , wherein quarantining the electronic message comprises executing Uniform Resource Locator (URL) code associated with the electronic message in a sand box.

5. The method of claim 1 , wherein determining the relationships between the first plurality of electronic message addresses and the second plurality of electronic message addresses comprises:

storing data representing a graph,

wherein the graph comprises nodes representing the first plurality of electronic message addresses and the second plurality of electronic message addresses, and the graph comprises edges extending among the nodes and representing pairwise relationships among the electronic message addresses associated with the nodes to which the edges connect.

6. The method of claim 1 , wherein determining the relationships between the first plurality of electronic message addresses and the second plurality of electronic message addresses comprises determining categories characterizing attachments communicated among the first plurality of electronic message addresses and the second plurality of electronic message addresses.

7. The method of claim 1 , wherein determining the relationships between the first plurality of electronic message addresses and the second plurality of electronic message addresses comprises determining whether embedded Uniform Resource Locator (URL) code has previously been communicated in a message associated with an electronic message address of the first plurality of electronic message addresses.

8. The method of claim 1 , wherein determining the relationships between the first plurality of electronic message addresses and the second plurality of electronic message addresses comprises applying an unsupervised machine learning classification.

9. The method of claim 1 , wherein determining the relationships between the first plurality of electronic message addresses associated with the first domain and the second plurality of electronic message addresses associated with the second domain comprises:

determining relationships between a first plurality of electronic message addresses associated with a first domain and a second plurality of electronic message addresses associated with a second domain:

determining a score based on the first weight and the second weight.

10. The method of claim 1 , wherein quarantining the electronic message comprises performing a sandbox analysis on the electronic message.

11. The method of claim 1 , wherein quarantining the electronic message comprises:

communicating a message to an intended recipient associated with the electronic message.

12. The method of claim 1 , further comprising:

applying a rule to the electronic message; and

allowing the electronic message to propagate to an intended recipient of the electronic message based on a result of applying the rule.

13. The method of claim 12 , wherein applying the rule comprises characterizing an attachment or an embedded program code associated with the electronic message.

14. An apparatus comprising:

a processor; and

a memory to store instructions that, when executed by the processor, cause the processor to:

apply unsupervised machine learning to determine relationships between a first plurality of electronic message addresses associated with a first domain and a second plurality of electronic message addresses associated with a second domain, wherein the application of the unsupervised machine learning comprises:

identifying a one-way communication between the first plurality of electronic message addresses and the second plurality of electronic message addresses;

assigning a first weight to the one-way communication;

identifying two-way communications between a first given message address of the first plurality of electronic message addresses and a second given message address of the second plurality of electronic message addresses;

assigning a second weight to the two-way communications based on a number-based criterion for the two-way communications such that the number-based criterion causes the second weight to correspond to a relatively higher strength for the two-way communications for a relatively larger number of the two-way communications and causes the second weight to correspond to a relatively lower strength for the two-way communications for a relatively smaller number of the two-way communications;

determine a relationship between the first domain and the second domain based on the first weight and the second weight; and

block transmission of an electronic message associated with a sender associated with the first domain to a recipient associated with the second domain based on the relationship between the first domain and the second domain.

15. The apparatus of claim 14 , wherein the instructions, when executed by the processor, further cause the processor to:

apply a rule to the electronic message; and

block transmission the electronic message based on a result of applying the rule.

16. The apparatus of claim 15 , wherein the instructions, when executed by the processor, further cause the processor to characterize an attachment or an embedded program code associated with the electronic message, and apply the rule based on the processor characterization.

17. The apparatus of claim 14 , wherein the instructions, when executed by the processor, further cause the processor to determine pairwise relationships among the first plurality of electronic message addresses and the second plurality of electronic message addresses.

18. An article comprising a non-transitory machine readable storage medium storing instructions that, when executed by a machine, cause the machine to:

determine pairwise relationships among entities associated with a first electronic mail organization and entities associated with a second electronic mail organization, wherein determining the pairwise relationships comprises:

identifying two-way communications between a first message address of the first electronic mail organization and a second message address of the second electronic mail organization; and

assigning a weight to the two-way communications based on a number-based criterion for the two-way communications such that the number-based criterion causes the weight to correspond to a relatively higher strength for the two-way communications for a relatively larger number of the two-way communications and causes the weight to correspond to a relatively lower strength for the two-way communications for a relatively smaller number of the two-way communications;

determine a relationship between the first electronic mail organization and the second electronic mail organization based on the weight; and

quarantine an electronic message originating from a sender associated with the first electronic mail organization in response to the relationship between the first electronic mail organization and the second electronic message mail organization meeting a second criterion.

19. The article of claim 18 , wherein the instructions, when executed by the machine, further cause the machine to apply a machine classification to data representing the pairwise relationships to determine a classification of the electronic message and control a receipt of the electronic message based on a result of the classification.

20. The article of claim 18 , wherein the instructions, when executed by the machine, further cause the machine to perform quarantining of the electronic message based on the pairwise relationships in response to a determination that the first electronic mail organization is not associated with a mass mail domain.