Method and system for reducing the false alarm rate of network intrusion detection systems
First Claim
1. A method for reducing the false alarm rate of network intrusion detection systems, comprising:
- receiving an alarm indicating a network intrusion may have occurred;
identifying characteristics of the alarm, including at least an attack type, a source address, a target address, an alarm severity, and an alarm description;
accessing a storage location;
determining whether an operating system fingerprint for a target host associated with the target address already exists in the storage location;
if the operating system fingerprint for the target host does not exist, then;
querying the target host for the operating system fingerprint;
receiving the operating system fingerprint that includes the operating system type from the target host;
comparing the attack type to the operating system type; and
indicating whether the target host is vulnerable to the attack based on the comparison;
if the operating system fingerprint for the target host does exist, then;
determining if a cache entry time for the target address is valid; and
if the cache entry time is invalid, then;
querying the target host for the operating system fingerprint;
receiving the operating system fingerprint that includes the operating system type from the target host;
comparing the attack type to the operating system type; and
indicating whether the target host is vulnerable to the attack based on the comparison;
if the cache entry time is valid, then;
comparing the attack type to the operating system type; and
indicating whether the target host is vulnerable to the attack based on the comparison.
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Accused Products
Abstract
According to one embodiment of the invention, a method for reducing the false alarm rate of network intrusion detection systems includes receiving an alarm indicating a network intrusion may have occurred, identifying characteristics of the alarm, including at least an attack type and a target address, querying a target host associated with the target address for an operating system fingerprint, receiving the operating system fingerprint that includes the operating system type from the target host, comparing the attack type to the operating system type, and indicating whether the target host is vulnerable to the attack based on the comparison.
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Citations
12 Claims
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1. A method for reducing the false alarm rate of network intrusion detection systems, comprising:
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receiving an alarm indicating a network intrusion may have occurred; identifying characteristics of the alarm, including at least an attack type, a source address, a target address, an alarm severity, and an alarm description; accessing a storage location; determining whether an operating system fingerprint for a target host associated with the target address already exists in the storage location; if the operating system fingerprint for the target host does not exist, then; querying the target host for the operating system fingerprint; receiving the operating system fingerprint that includes the operating system type from the target host; comparing the attack type to the operating system type; and indicating whether the target host is vulnerable to the attack based on the comparison; if the operating system fingerprint for the target host does exist, then; determining if a cache entry time for the target address is valid; and if the cache entry time is invalid, then; querying the target host for the operating system fingerprint; receiving the operating system fingerprint that includes the operating system type from the target host; comparing the attack type to the operating system type; and indicating whether the target host is vulnerable to the attack based on the comparison; if the cache entry time is valid, then; comparing the attack type to the operating system type; and indicating whether the target host is vulnerable to the attack based on the comparison. - View Dependent Claims (2, 4)
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3. The method of claim , further comprising:
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monitoring a dynamic configuration protocol server; detecting that a lease issue has occurred for a new target host; querying the new target host for a new operating system fingerprint; receiving the new operating system fingerprint from the new target host; and storing the new operating system fingerprint of the new target host in the storage location for a length of time.
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5. A computer-readable non-transitory storage medium embodying software this is operable when executed by a computer system to:
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receive an alarm indicating a network intrusion may have occurred; identify characteristics of the alarm, including at least an attack type, a source address, a target address, an alarm severity, and an alarm description; access a storage location; determine whether an operating system fingerprint for a target host associated with the target address already exists in the storage location; if the operating system fingerprint for the target host does not exist, then; query the target host for the operating system fingerprint; receive the operating system fingerprint that includes the operating system type from the target host; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison; if the operating system fingerprint for the target host does exist, then; determine if a cache entry time for the target address is valid; and if the cache entry time is invalid, then; query the target host for the operating system fingerprint; receive the operating system fingerprint that includes the operating system type from the target host; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison; if the cache entry time is valid, then; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison. - View Dependent Claims (6, 7, 8)
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9. An apparatus comprising:
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a communication interface; memory containing instructions for execution by a processor; and the processor, operable when executing the instructions to; receive an alarm indicating a network intrusion may have occurred; identify characteristics of the alarm, including at least an attack type, a source address, a target address, an alarm severity, and an alarm description; access a storage location; determine whether an operating system fingerprint for a target host associated with the target address already exists in the storage location; if the operating system fingerprint for the target host does not exist, then; query the target host for the operating system fingerprint; receive the operating system fingerprint that includes the operating system type from the target host; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison; if the operating system fingerprint for the target host does exist, then; determine if a cache entry time for the target address is valid; and if the cache entry time is invalid, then; query the target host for the operating system fingerprint; receive the operating system fingerprint that includes the operating system type from the target host; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison; if the cache entry time is valid, then; compare the attack type to the operating system type; and indicate whether the target host is vulnerable to the attack based on the comparison. - View Dependent Claims (10, 11, 12)
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Specification