Method for preventing ransomware attacks on computing systems
A method for preventing ransomware attacks on a computing system. By controlling the access to a calling interface through which cryptographic functions, such as the random number generator, can be accessed to generate strong encryption keys the method allows to efficiently terminate cryptographic ransomware attacks on the system before they can start doing any damage. If the access to the cryptographic functions, such as the random number generator, is not granted, the ransomware is unable to build a strong encryption key, and it is unable to deploy its intended effect.
1. A computer-implemented method for preventing ransomware attacks on a computing system, the computing system having access to computing resources including a source of randomness, which comprises random number or pseudo-random number generation means, and which are accessible through a calling interface means, the computer-implemented method comprising the following steps:
providing predetermined requirements describing a permissible call to said source of randomness comprising random number or pseudo-random number generation means through said calling interface means in a memory element;
monitoring a usage of said calling interface means using a monitoring means, wherein monitoring the usage includes obtention of data identifying a call to said source of randomness, wherein the data identifying said call comprises data identifying a calling process; and
determining if the data identifying the call complies with the predetermined requirements and blocking said call to said source of randomness when it is determined that the data identifying said call does not comply with said predetermined requirements, wherein the predetermined requirements comprise data identifying at least one calling process that is allowed to access said source of randomness, and wherein said call is blocked unless the data identifying the calling process is comprised in the data identifying at least one allowed calling process.
2. The computer-implemented method according to claim 1 , wherein said source of randomness comprises a cryptographically secure random number generator.
3. The computer-implemented method according to claim 1 , wherein said calling interface means comprise an application programming interface providing access to said source of randomness.
4. The computer-implemented method according to claim 1 , wherein blocking said call comprises terminating a corresponding calling process.
5. The computer-implemented method according to claim 1 , wherein said monitoring means are part of the computing system's operating system.
6. The computer-implemented method, according to claim wherein the source of randomness comprises a source of entropy.
7. A system for preventing ransomware attacks on a computing system, the computing system having access to computing resources including a source of randomness, which comprises random number or pseudo-random number generation means, and which are accessible through a calling interface means, the system comprises a memory storing instructions when executed by a processor cause the processor to:
provide predetermined requirements describing a permissible call to the source of randomness comprising random number or pseudo-random number generation means through the calling interface means in a memory element;
monitor a usage of the calling interface means using a monitoring means, wherein monitoring the usage includes obtention of data identifying a call to said source of randomness, wherein the data identifying the call comprises data identifying a calling process; and
determine if the data identifying the call complies with the predetermined requirements and blocking the call to the source of randomness when it is determined that the data identifying the call does not comply with the predetermined requirements, wherein the redetermined requirements comprise data identifying at least one calling process that is allowed to access the source of randomness, and wherein the call is blocked unless the data identifying the calling process is comprised in the data identifying at least one allowed calling process.
8. The system of claim 6 , wherein the source of randomness comprises a cryptographically secure random number generator.
9. The system of claim 7 , wherein the calling interface means comprise an application programming interface providing access to the source of randomness.
10. The system of claim 7 , wherein blocking the call comprises terminating a corresponding calling process.
11. The system of claim 6 , wherein the monitoring means are part of the computing system's operating system.
12. The system of claim 6 , wherein the source of randomness comprises a source of entropy.
13. A non-transitory computer readable storage medium storing instructions that when executed by a computer, which includes a processor perform a method, the method comprising:
providing predetermined requirements describing a permissible call to a source of randomness of a computing system that includes a random number or pseudo-random number generation means through a calling interface means;
monitoring a usage of the calling interface means using a monitoring means, wherein monitoring the usage includes obtention of data identifying a call to said source of randomness, wherein the data identifying the call comprises data identifying a calling process; and
determining if the data identifying the call complies with the predetermined requirements and blocking the call to the source of randomness when it is determined that the data identifying the call does not comply with the predetermined requirements, wherein the predetermined requirements comprise data identifying at least one calling process that is allowed to access the source of randomness, wherein the call is blocked unless the data identifying the calling process is comprised in the data identifying at least one allowed calling process.
14. The non-transitory computer readable storage medium of claim 13 , wherein blocking the call comprises terminating a corresponding calling process.