Fast-flux detection utilizing domain name system information

1. A method comprising steps of:

determining a first set of features from domain name system (DNS) information stored in at least one database of a computer network, the first set of features being defined over a domain accessed by a plurality of network devices of the computer network;

determining a second set of features from the DNS information, the second set of features being defined over internet protocol (IP) addresses returned for the domain;

computing a fast-flux score based on the first and second sets of features;

utilizing the fast-flux score to characterize fast-flux activity relating to the domain; and

generating a fast-flux activity indicator in a network security system of the computer network in conjunction with the characterization of fast-flux activity relating to the domain;

wherein at least a portion of the first set of features is based on a number of distinct date-based pairs with each such pair comprising one of an IP address and an autonomous system number and an associated date;

wherein at least a portion of the second set of features is based on a number of distinct roots associated with one of an IP address and an autonomous system number; and

wherein the steps are performed by at least one processing device comprising a processor coupled to a memory.

2. The method of claim 1 wherein the DNS information comprises DNS response logs.

3. The method of claim 1 wherein computing a fast-flux score based on the first and second sets of features comprises:

weighting at least a subset of the first set of features;

weighting at least a subset of the second set of features; and

computing the fast-flux score as a specified function of the weighted first set of features and the weighted second set of features.

4. The method of claim 1 wherein computing a fast-flux score based on the first and second sets of features comprises setting the fast-flux score to a zero value if a number of distinct IP addresses in the IP addresses returned for the domain is less than or equal to a threshold minimum number of distinct IP addresses.

5. The method of claim 1 wherein computing a fast-flux score based on the first and second sets of features comprises setting the fast-flux score to a null value if a number of responses for the domain is less than or equal to a threshold minimum number of responses.

6. The method of claim 1 wherein determining a first set of features comprises determining one or more of:

A. number of distinct IP addresses returned for the domain;

B. median of the number of distinct IP addresses per response;

C. number of distinct autonomous system numbers (ASNs) to which the IP addresses belong;

D. median of the number of distinct ASNs to which the IP addresses belong per response;

E. number of distinct (IP address, date) pairs divided by the number of distinct IP addresses;

F. number of distinct (ASN, date) pairs divided by the number of distinct ASNs to which the IP addresses belong; and

G. number of distinct destination IP addresses.

7. The method of claim 6 wherein determining a second set of features comprises determining one or more of:

H. number of distinct destination IP addresses appearing with any of the IP addresses returned for the domain;

I. median of the number of distinct destination IP addresses per returned IP address;

J. number of distinct roots appearing with any of the IP addresses;

K. median of the number of distinct roots per returned IP address;

L. median of the number of distinct returned IP addresses appearing with any of the ASNs per ASN;

M. median of the number of distinct destination IP addresses appearing with any of the ASNs per ASN; and

N. median of the number of distinct roots appearing with any of the ASNs per ASN.

8. The method of claim 7 wherein for detection of fast-flux types that return a single IP address per response, features B and D are not utilized in computing the fast-flux score.

9. The method of claim 7 wherein computing a fast-flux score based on the first and second sets of features comprises computing the fast-flux score as:

FF=( A^a*B^b*C^c*D^d )/( E^e*F^f*G^g*H^h*I^i*J^j*K^k*L^l*M^m*N^n ),

where FF denotes the fast-flux score and a, b, . . . n denote weights for respective ones of the features A, B, . . . N.

10. The method of claim 1 wherein computing a fast-flux score based on the first and second sets of features further comprises computing a normalized fast-flux score from a fast-flux score FF as follows:

NFF=FF/(μ+FF),

where NFF denotes the normalized fast-flux score and, μ denotes a configurable normalization parameter.

11. The method of claim 1 wherein the utilizing and generating comprise:

comparing the fast-flux score to a threshold; and

generating an indicator of the presence or absence of fast-flux activity based on a result of the comparing.

12. The method of claim 1 wherein the domain comprises a root having a plurality of sub-domains and determining the first and second sets of features comprises determining the first and second sets of features in an aggregate manner over the plurality of sub-domains of the domain root.

13. The method of claim 1 wherein determining the first and second sets of features comprises ignoring at least one of:

DNS responses in which all returned IP addresses are reserved IP addresses;

IP addresses that are reserved IP addresses; and

IP addresses that do not include ASN information.

14. An article of manufacture comprising a processor-readable storage medium having stored therein program code of one or more software programs, wherein the program code when executed by at least one processing device causes said at least one processing device:

to determine a first set of features from domain name system (DNS) information stored in at least one database of a computer network, the first set of features being defined over a domain accessed by a plurality of network devices of the computer network;

to determine a second set of features from the DNS information, the second set of features being defined over internet protocol (IP) addresses returned for the domain;

to compute a fast-flux score based on the first and second sets of features;

to utilize the fast-flux score to characterize fast-flux activity relating to the domain; and

to generate a fast-flux activity indicator in a network security system of the computer network in conjunction with the characterization of fast-flux activity relating to the domain;

wherein at least a portion of the first set of features is based on a number of distinct date-based pairs with each such pair comprising one of an IP address and an autonomous system number and an associated date; and

wherein at least a portion of the second set of features is based on a number of distinct roots associated with one of an IP address and an autonomous system number.

15. An apparatus comprising:

at least one processing device comprising a processor coupled to a memory;

said at least one processing device being configured:

to determine a first set of features from domain name system (DNS) information stored in at least one database of a computer network, the first set of features being defined over a domain accessed by a plurality of network devices of the computer network;

to determine a second set of features from the DNS information, the second set of features being defined over internet protocol (IP) addresses returned for the domain;

to compute a fast-flux score based on the first and second sets of features;

to utilize the fast-flux score to characterize fast-flux activity relating to the domain; and

to generate a fast-flux activity indicator in a network security system of the computer network in conjunction with the characterization of fast-flux activity relating to the domain;

wherein at least a portion of the first set of features is based on a number of distinct date-based pairs with each such pair comprising one of an IP address and an autonomous system number and an associated date; and

wherein at least a portion of the second set of features is based on a number of distinct roots associated with one of an IP address and an autonomous system number.

16. The apparatus of claim 15 wherein the apparatus comprises a fast-flux detector.

17. The apparatus of claim 16 wherein the fast-flux detector is configured to weight at least a subset of the first set of features, to weight at least a subset of the second set of features, and to compute the fast-flux score as a specified function of the weighted first set of features and the weighted second set of features.

18. The apparatus of claim 16 wherein the fast-flux detector is configured to compare the fast-flux score to a threshold, and to generate an indicator of the presence or absence of fast-flux activity based on a result of the comparison.

19. The article of manufacture of claim 14 wherein the domain comprises a root having a plurality of sub-domains and determining the first and second sets of features comprises determining the first and second sets of features in an aggregate manner over the plurality of sub-domains of the domain root.

20. The article of manufacture of claim 14 wherein determining the first and second sets of features comprises ignoring at least one of:

DNS responses in which all returned IP addresses are reserved IP addresses;

IP addresses that are reserved IP addresses; and

IP addresses that do not include ASN information.