Patent Application
20080072325
An example embodiment of the present invention should become apparent from the following description, which is given by way of example only, of a preferred but non-limiting embodiment, described in connection with the accompanying figures.
The following modes, given by way of example only, are described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.
In the figures, incorporated to illustrate features of an example embodiment, like reference numerals are used to identify like parts throughout the figures.
A particular embodiment of the present invention can be realised using a processing system, an example of which is shown in
Input device 106 receives input data 118 and can comprise, for example, a keyboard, a pointer device such as a pen-like device or a mouse, audio receiving device for voice controlled activation such as a microphone, data receiver or antenna such as a modem or wireless data adaptor, data acquisition card, etc. Input data 118 could come from different sources, for example keyboard instructions in conjunction with data received via a network. Output device 108 produces or generates output data 120 and can comprise, for example, a display device or monitor in which case output data 120 is visual, a printer in which case output data 120 is printed, a port for example a USB port, a peripheral component adaptor, a data transmitter or antenna such as a modem or wireless network adaptor, etc. Output data 120 could be distinct and derived from different output devices, for example a visual display on a monitor in conjunction with data transmitted to a network. A user could view data output, or an interpretation of the data output, on, for example, a monitor or using a printer. The storage device 114 can be any form of data or information storage means, for example, volatile or non-volatile memory, solid state storage devices, magnetic devices, etc.
In use, the processing system 100 is adapted to allow data or information to be stored in and/or retrieved from, via wired or wireless communication means, the at least one database 116. The interface 112 may allow wired and/or wireless communication between the processing unit 102 and peripheral components that may serve a specialised purpose. More than one input device 106 and/or output device 108 can be provided. It should be appreciated that the processing system 100 may be any form of terminal, server, specialised hardware, or the like.
The processing system 100 may be a part of a networked communications system. Processing system 100 could connect to a network, for example the Internet or a WAN. Input data 118 and output data 120 could be received from or communicated to other devices, such as a server, via the network. The network may form part of, or be connected to, the Internet, and may be or form part of other communication networks, such as LAN, WAN, ethernet, token ring, FDDI ring, star, etc., networks, or mobile telephone networks, such as GSM, CDMA or 3G, etc., networks, and may be wholly or partially wired, comprising for example optical fibre, or wireless networks, depending on a particular implementation.
Referring now to
When a user at the client processing system 230 attempts to download data such as software from the remote processing system 210, request data 240 is generated by the client processing system 230 and transferred to the proxy server 220. Generally, the proxy server 220 then transfers the request data 240 to the remote processing system 210. In accordance with the request data 240, the remote processing system 210 generates response data 250 which is transferred to the proxy server 220. The proxy server 220 analyses the response data to determine if the response data is malicious. If malicious, at least as a portion of the response data 250 is modified to restrict the client processing system 230 being compromised. Analysed response data 260 is then transferred to the client processing system 230 from the proxy server 220.
Referring now to
In particular, at step 310 the method 300 comprises the proxy server 220 receiving response data 250 to a request 240 to download data from the remote processing system 210. At step 320, the method 300 comprises analysing the response data to determine if the response data is malicious. At step 330, in the event that the response data is malicious, the method 300 proceeds to step 340 which comprises the proxy server 220 modifying the response data 250 so as to restrict the client processing system 230 being compromised with the malicious software of the response data 250. At step 350 the method 300 comprises transferring the analysed response data 260 to the client processing system 230.
Referring now to
In particular, the proxy server 220 comprises an analysis module 224, a modification module 225 and a cache module 226.
When the client processing system 230 transfers request data 240 to the proxy server 220, the cache module 226 analyses the request 240 to determine if the request 240 has previously been serviced. The cache module 226 is configured to store analysed response data 260 that has been previously transferred to the client processing system 230.
In one form, the cache module 226 may store a hash value of each serviced request 240 and the associated analysed response 260. The cache module 226 may be configured to determine a hash value for the received request 240, wherein records of previously serviced requests 240 are searched using the determined hash value to determine if the request 240 has been responded to previously. In the event that the received request data 240 has been previously serviced, the cache module 226 retrieves the relevant analysed response data 260 which is transferred to the client processing system 230.
In the event that the cache module 226 does not comprise a recorded response 260 to the particular request 240, the request data 240 is transferred to the server processing system 210. The operation of the analysis module 224 will be discussed in more detail below.
Results 256 of the analysis performed by the analysis module 224 are then transferred to the modification module 225. The response data 250 is also transferred to the modification module 225. The modification module 225 can modify, if appropriate, the software in accordance with the results 256 of the analysis. For example, the results 256 may indicate that a portion of the software is malicious. Therefore, the modification module 225 may remove the malicious portion of the software from the response data 250. The modification module 225 may optionally replace the malicious portion of the software with a non-malicious portion of software, as will be explained in more detail below. In some instances, the entire downloaded software may be considered malicious and as such may be either removed or replaced with a non-malicious version of the software, as will also be explained in more detail below. If the analysis results 256 indicate that the software is non-malicious, then the software does not require modification.
A wrapper component can be comprised in the analysed response data 260 to indicate scanning data. The scanning data may be indicative of a version of a signature database which was used by the analysis module 224 to analyse the response data 250. The scanning data may be indicative of at least one of: the time and/or date which the scan was performed; the type of scanning modules used by the analysis module 224; a version number indicative of the analysis module 224; a size of the downloaded software; file location; and whether the downloaded software is code-signed.
When the user receives the analysed response data 260 and attempts to execute the downloaded software, the wrapper component may be executed by the client processing system, displaying to the user the scanning data. The wrapper component can provide a prompt to the user requesting confirmation that, based on the scanning data, the user still wishes to execute the software. The user may indicate, using the input device of the client processing system 230, that the software is to be executed or that the software is to be deleted or quarantined for further analysis.
Optionally, the modification module 225 may accept a code-signed prompt, such that the user at the client processing system 230 is not prompted to perform the acceptance.
In the event that the software, or a portion thereof, is to be replaced, the modification module 225 may generate and transfer a replacement request 258 to the cache module 226. The replacement request 258 can indicate the software of the response data 250. For example, information such as a name of the software, the version of the software may be comprised in the replacement request 258, and the network address of the server processing system 210 which transferred the response data 250.
In response to the replacement request 258, the cache module 226 performs a search of recorded analysed response data 260 to determine if a similar request had been previously serviced for the requested software. In the event that the cache module 226 determines a previous non-malicious version of the software had been provided to a client processing system 230 in the past, the cache module 226 may transfer the closest matching software 259, or portion thereof, back to the modification module 225. The modification module 225 may then use the closest matching software 259, or portion thereof, to modify the response data 250 so as to restrict the client processing system 230 being compromised with malicious software. For example, the modification module 225 may remove a particular malicious file from the software and replace it with an earlier non-malicious version of the file which had previously been transferred to the client processing system 230. Alternatively, the entire malicious software may be removed from the response data 250, and the non-malicious version of the software may be comprised.
The analysed response data 260 is then transferred from the modification module 225 to the cache module 226 for caching. Once the cache module 226 has cached the analysed response data 260, the analysed response data 260 is then transferred from the cache module 226 to the client processing system 230.
Referring now to
In particular, at step 505 the method 500 comprises the client processing system 230 generating request data 240 to download software from the remote processing system 210. This may be performed by the user selecting, using input device 106, a hyperlink in a web-page available on the Internet, wherein the hyperlink allows software to be downloaded from the remote processing system 210. At step 510, the method 500 comprises the client processing system 230 transferring the request data to the proxy server 220.
At step 515, the method 500 comprises the proxy server 220 initiating the cache module 226 to determine whether an analysed response 260 has previously been transferred to a client processing system 230 for the requested software. At step 520, if the software has previously been requested and suitable analysed response data 260 is available in the cache module 226, the method 500 proceeds to step 521 where the cache module 261 transfers to the client processing system 230 previously transferred analysed response data 260. In the event that the cache module 226 does not comprise suitable analysed response data 260 for the software requested, the method 500 proceeds to step 525 where the cache module 226 transfers the request data 240 to the remote processing system 210.
At step 530, the method 500 comprises the remote processing system 210 transferring response data 250 to the proxy server 220, wherein the response data 250 is indicative of the requested software.
At step 535, the method 500 comprises the analysis module 224 analysing the software of the response data 250 to determine if the software is malicious. At step 540, in the event that the software, or a portion thereof, is determined to be malicious, the method proceeds to step 545. In the event that the software was non-malicious, the method proceeds to step 550.
At step 545, the method 500 comprises the modification module 225 modifying at least a portion of the response data 250 to restrict the client processing system 230 being compromised with malicious software. This step can comprise removing the software from the response data 250 and modifying the response data to indicate that the software was malicious. In another form, a malicious portion of the software can be removed. In another form, the software, or a portion thereof, can be replaced with non-malicious software, or portion thereof, retrieved from the cache module 226 as has previously been discussed.
At step 550, the wrapper component is added to the analysed response data 260, wherein the wrapper component is indicative of scan data. In other optional forms, any code-signing provided with the response data can be accepted.
At step 555, the method 500 comprises the cache module 226 storing the analysed response data 260. The cache module 226 records in a store, such as a database, the analysed response data 260 in association with the request data 240. The cache module 261 may calculate a hash value for the analysed response data 260 and/or the request data 240 and store this in the database such that the cache 226 can be easily searched. Other information may also be stored in the cache module 226 such as the date and/or time which the software was requested such that unsuitable recordings in the cache module 226 can be removed when appropriate.
At step 560, the cache module 226 transfers the analysed response data 260 to the client processing system 230. The analysed response data 260 may comprise the requested software. However, if the software transferred from the remote processing system 210 was determined to be malicious, then it may be possible that the software, or a portion thereof, may have been removed. It is also possible that a replacement version of the software may be comprised in the analysed response data 260, wherein the different version of the software, or portion thereof, is considered to not be malicious. In another form, the analysed response data 260 may comprise modified software, wherein one of the software's components may have been modified or replaced.
The analysed response data 260 may indicate to the user what modification, if any occurred by the proxy server 220, and the reasons for any modification.
Referring now to
In particular, the analysis module 224 can comprise the modules of the malicious a cryptographic hash module 2241, a checksum module 2242, a disassembly module 2242, a black-list/white-list module 2244, and a pattern matching module 2245.
The cryptographic hash module 2241 of the analysis module 224 is configured to generate a cryptographic hash value of at least a portion of the software. As the cryptographic hash value can be used as an identity, the cryptographic hash value can be used in comparisons with the blacklist/whitelist module 2244 to determine whether the at least a portion of the software is malicious.
The checksum module 2242 of the analysis module 224 is configured to determine a checksum of the software. The checksum can be compared to a database (blacklist/whitelist module 2244) to determine whether the software is malicious.
The pattern matching module 2245 of the analysis module 224 is configured to search the software for particular patterns of strings, instructions, or events which are indicative of malicious activity. The pattern matching module 2245 may operate in combination with the disassembly module 2243 of the analysis module 224.
The disassembly module 2243 is configured to disassemble binary code of the software such that the disassembly module 2243 determines processing system instructions. The processing system instructions of the software can then be used by the pattern matching module 2245 to determine whether the software is malicious. Although strings of instructions can be compared by the pattern matching module 2245, the pattern matching module 2245 may be configured to perform functional comparisons of groups of instructions to determine whether the functionality of software is indicative of malicious software.
The blacklist/whitelist module 2244 of the analysis module 224 comprises a list of malicious and/or non-malicious software. The blacklist/whitelist module 2244 may be provided in the form of a table or database which comprises data indicative of malicious and non-malicious software. The table may comprise checksums and cryptographic hash values for malicious and non-malicious software. The data stored in the blacklist/whitelist module 2244 can be used to determine whether the software is malicious or non-malicious.
In one form, statistical processes, fuzzy logic processes and/or heuristical processes can be used in combination with the related entity rules, the starting entity rules, and/or the malicious assessment rules to determine whether a rule has been satisfied by an entity of the software.
The embodiments illustrated may be implemented as a software package or component. Such software can then be used to pro-actively seek to determine one or more malicious entities. Various embodiments can be implemented for use with the Microsoft Windows operating system or any other modern operating system. The embodiments described throughout can also be implemented via hardware, or a combination of hardware and software.
The embodiments described can be used to detect and remove malicious software from a network request, such as a HTTP request or FTP download. While the current implementation is Linux (eg: Squid with ICAP enabled, WINE, QEMU) and Windows specific, the disclosed methods and systems may be applied to modern operating systems on any device comprising embedded gateway appliances such as routers and firewalls.
The cache module 226 may apply one or more algorithms to remove unsuitable cached analysed response data 260. Such algorithms may comprise Least Recently Used (LRU) and Least Frequently Used (LFU).
In one form, the proxy server can be configured to determine if the data which has been downloaded is executable. If in the event that the data is executable, the proxy server uses an emulated operating system to execute the data. Events that occur are then monitored in the emulated operating system during execution of the data. The events monitored may be specific events associated with malicious behaviour or all particular events that occur in the emulated operating system are monitored. The events may be recorded in memory such as a data log file or database. The events may be monitored using interception techniques previously discussed, wherein a hook function may be used to monitor events that occur in the processing system executing the data. The events are then analysed to determine if at least a portion of the response data is malicious. The proxy server may use the analysis module to analyse the recorded events. In the event that at least a portion of the response data is malicious, the response data is modified accordingly. A detailed explanation of monitoring behaviour of malicious software is described in the Applicant's following co-pending applications, the content of which is herein by incorporated by cross-reference: co-pending U.S. patent application Ser. No. 11/829,592 and co-pending Australian Patent application AU2007203543 entitled “Threat Identification”; co-pending U.S. patent application Ser. No. 11/829,608 and co-pending Australian Patent application AU2007203534 entitled “Real Time Malicious Software Detection”; and co-pending U.S. patent application Ser. No. 11/780,113 and co-pending Australian Patent application AU2007203373 entitled “Detecting Malicious Activity”.
Optional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.
Although a preferred embodiment has been described in detail, it should be understood that various changes, substitutions, and alterations can be made by one of ordinary skill in the art without departing from the scope of the present invention.
An example piece of pseudocode for implementing a method of restricting malicious software compromising the client processing system is provided below:
This application claims the benefit of priority from U.S. Provisional Patent Application No. 60/844,574 filed Sep. 14, 2006, and is incorporated by referenced.
| Number | Date | Country | |
|---|---|---|---|
| 60844574 | Sep 2006 | US |
