KR20040092707A - Spam/junk mail blocking system controlled by on-line spam filter and imap server - Google Patents

Abstract

PURPOSE: A system for blocking a spam mail using an online spam blocking filter and an IMAP(Interactive Mail Access Protocol) server method is provided to enable general users to block the spam mail with only the given online spam blocking filter without separate setting by transferring the online spam blocking filter analyzing information of the spam mail to an MUA(Mail User Agency) of a PC. CONSTITUTION: The system comprises a remote server(400) providing a new online spam blocking filter by connecting to the network such as the Internet(300), a POP3(Post Office Protocol version 3) proxy server(100a) receiving a mail from a mail server(200), an IMAP server(100b), and the MUA(100c) supporting the POP3. After checking the version of the latest online spam blocking filter by connecting to the remote server, the POP3 proxy server downloads the new online spam blocking filter if the online spam blocking filter of the MUA is an old version. The MUA blocks the spam mail by using the online spam blocking filter provided through the online without separately generating the spam blocking filter.

Description

Spam blocking system using online spam blocking filter and IMAP server method {SPAM / JUNK MAIL BLOCKING SYSTEM CONTROLLED BY ON-LINE SPAM FILTER AND IMAP SERVER}

The present invention relates to a spam mail blocking system using an online spam blocking filter and an IMAP server method. In particular, an online spam blocking filter that analyzes spam mail information under an existing client / server system environment includes a MUA (Mail User) of a personal PC. It is related to the spam blocking system using the online spam blocking filter and the IMAP server method, which enables individual users to block the spam mail only with the given online spam blocking filter without additional setting.

With the development of the current Internet, e-mail has become a common means of communication among Internet users. However, as e-mail itself is used for commercial purposes, spam and junk mail are polluting the Internet environment. Even though the recipients don't want it, spam mails that are delivered to randomly extracted mail addresses pay unilaterally for time, mental and economic losses.

In order to filter spam mails, a technology for filtering spam mails by parsing the header of mails at the Simple Mail Transfer Protocol (Smtp) stage of a mail server is used. This is called server-based message filtering technology and is currently used in commercial and non-commercial mail servers such as sendmail and qmail. However, when managing a large amount of mail, the analysis of spam mail by analyzing such header information for each received mail is used only selectively because it is a load and time-consuming task.

The Mail Transfer Agent (MTA) uses header information to limit junk or spam mail. In foreign countries, commercial and free services are provided that provide address lists of known spammers. Therefore, a specific MTA can reject a message by applying a spam list (Black List & White List) to the mail requested through its own mail server. MTA operators restrict the ability to relay messages from any location and generally allow messages to be relayed only if they come from their MTA's own domain. Sendmail and some MTAs provide such anti-spam features. The MTA delivers it to the Mail Delivery Agent (MDA) for delivery to other MTAs or other users, who receive the message from the MTA and write it to the recipient's mailbox on the local file system. At this time, the MDA filters the mail by executing spam filtering on its own or by calling an external program that performs the filtering function.When sending the mail, the MUA (Mail User Agency) sends the mail to the MTA using smtp on the Internet. If the file exists, it is delivered using the MIME and type standards.

In addition to parsing the header information as described above, a method generally used in a mail server is IP blocking technology. This is mainly used by large ISPs. This is a method of sharing the IP of the mail server suspected of sending Junk mail to the black list, and rejecting all mails sent from this site by smtp. In addition, a patent-pending blocking technology called Dynamic IP blocking is being applied by reinforcing the automatic detection of spam mail sending IP.

When using the server-based spam blocking method, the following problems occur.

1) In the case of Korean characters, their structure is different from that of English, so the spam list service provided in foreign countries is less effective in blocking spam mails. In addition, spammers are using their mail domains, mail addresses, and IP addresses appropriately, so spam lists alone are not effective in blocking spam. Therefore, in order to increase the spam blocking rate, a content filtering technique is required.

2) You may suffer mental and physical damage by not receiving emails to be received properly. In this case, AOL installed and operated a spam blocking system as a measure to protect its members from a myriad of spam messages, and hundreds of thousands of emails were sent to AOL accounts by some customers of Earthlink, one of the spam watchers. This was not delivered to the intended recipient and was blocked or deleted. Even if the mail is received as spam mail, it is necessary to provide a system that allows the user to manage it (processed by the user as spam mail or normal mail, archive and delete spam mail).

3) In the case of server-based spam blocking, there is a situation of invasion of personal privacy. In other words, organizations must obtain the user's consent in order to install such a server-level spam blocking system in the enterprise. In other words, even if there is a leak or omission of personal information, it can be installed only after receiving all written consent from the individual to accept it and use the system. This is a serious problem of personal privacy, and individuals are forced to bear this damage.

4) Under the Internet environment, adult mails that are harmful to adolescents through e-mails are directly addressed in the form of spam mails / junk mails. Existing spam list method has a limitation that can not block such adult mail completely.

Thus, the present invention has been made to solve the problems of the prior art. The object of the present invention is to deliver an online spam blocking filter that analyzes the spam mail information in the existing client / server system environment to the MUA (Mail User Agency) of the personal PC, so that only individual online spam blocking filters are given to individual users without additional settings. It is to provide a system that can block spam mails.

Another object of the present invention is to manage the spam mail detected using the online spam blocking filter separately according to the protocol using the IMAP / POP3 mail receiving server method and finally the management of the stored spam mail (spam spam option) By the user to implement the spam mail management method, such as the return of spam mail to normal mail, the storage and deletion of spam mail, so that errors caused by the spam mail blocking system can be corrected.

Still another object of the present invention is to provide an administrator function through encryption setting in order to block access to harmful adult mail.

Still another object of the present invention is to provide a technical method for minimizing tangible / intangible loss caused by spam mail, and to process spam mails on a personal PC using an online spam filter provided by a remote server. To provide a way to do it.

Another object of the present invention is to provide a management system that can minimize errors due to inaccuracy of the spam mail blocking system by a user checking the processed spam mail. It is intended to provide a technical solution to prevent tacking and to prevent pornographic / spam mail from being exposed to young people.

1 is a block diagram showing a mail receiving process concept.

2 is a block diagram showing the configuration of a spam mail blocking system;

3 is a block diagram showing the configuration and operation of a remote server.

4 is a block diagram showing a configuration of an online spam blocking filter.

5 is a block diagram illustrating a spam mail classification method performed in MUA.

6 is a flowchart showing an example of a spam mail blocking scheme;

7 is a flowchart showing another example of a spam mail blocking scheme;

8 is a block diagram for explaining an access right setting for a spam mailbox.

<Description of the symbols for the main parts of the drawings>

100: spam mail blocking system

200: mail server

300: internet network

400: remote server

500: Online spam blocking filter

Spam mail blocking system of the present invention for achieving the object of the present invention provides a system for providing an online spam blocking filter that provides a statistically defined content filtering (mail content filtering) filter ; A remote server system connected to the Internet for storing and distributing the online spam blocking filter ; And a MUA system that receives an online spam blocking filter from a remote server system and manages spam mail using POP3 proxy method and IMAP method.

Preferably, the online spam blocking filter providing system may include: a DB system capable of periodically updating its information by receiving periodically updated information stored and stored in a commercial database or file system; And it shall be composed mail header information to analyze the spam filters to detect spam filter _3 _2 and Junk e-mail to detect spam based on message body content and spam filters _1 to detect spam MUA It includes an online spam blocking filter system that complements spam filter_1 and spam filter_3 by first applying address book information and spam filter_2.

Preferably, the spam filter _1 of the online spam blocking filter system includes a list collected based on mail sender address information, mail domain address information, mail send date information, mail path information, and return-Path information; The spam filter_2 includes a statistically collected list for detecting specific string inclusion, specific link inclusion, and specific character set; Spam filter _3 includes a list for detecting spam mail through mail size limitation, recipient and reference number limitation, and attachment file size limitation.

The spam blocking system automatically filters the online spam blocking filter from the remote server system where the online spam blocking filter is stored and from the MUA connected through the internet or wired or wireless network to access the server and download the online spam blocking filter. It can be configured to be updated and reflected in the MUA.

MUA system classifies spam mail and normal mail by using online spam blocking filter provided from remote server connected through internet or network, and spam mail is used for IMAP server and normal mail is general POP3 server using POP3 Proxy server method on personal PC. It can be configured to store in.

Preferably, the spam blocking system includes a security method performing means for allowing a mail authorized as a spam stored in an IMAP server to be searched by only an authorized user by applying a specific encryption method; Means for performing a feedback method having a function of later processing normal mail stored in a POP3 server as spam mail; Means for processing spam mail stored in the IMAP server later as normal mail; And means for providing a deletion cycle and an automatic deletion function of the spam mail for managing the spam mail stored in the IMAP server.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention applies to existing MUAs that support POP3 and IMAP protocols. This applies to client / server systems that implement MRA (Mail Retrieval Agent) in POP3 and IMAP.

1 is a block diagram illustrating a process of delivering a mail to a MUA in a general mail system. The mail server 200 stores the received mail in a personal local area to which the local MDA 200b is assigned and connects the POP daemon 200d to the TCP port 110 to transmit the message to the MUA 100c.

2 shows a configuration of a spam blocking system according to the present invention. The spam blocking system is connected to a network such as the Internet and supports a remote server 400 providing an online spam blocking filter, a POP3 proxy server 100a, an IMAP server 100b, and POP3 that receive and process mail from a mail server. It is composed of the MUA (100c). The POP3 Proxy server 100a checks the version of the latest online spam blocking filter by connecting to a remote server (web server) and downloads the old online spam blocking filter held by the MUA. Even though MUA does not create an anti-spam filter separately, it is characterized by blocking the spam mail by using an online anti-spam filter provided online.

3 is a block diagram for explaining the configuration and operation of the remote server 400 of FIG. The remote server provides a new online spam blocking filter by the administrator, the presentation tool (400a) responsible for updating, the Logic Tool (400b), DataBase (400c), which is in charge of checking the filter version in connection with MUA, Web server structure (400d) for providing an online spam blocking filter to the MUA, characterized in that. The remote server operates on a network connected to the Internet to deliver an online spam blocking filter to a personal PC connected to a LAN, WAN, or Internet network. Looking at the operation of the remote server 400 uploads the latest online spam blocking filter 500 to the remote server (upload). This is possible by updating the relevant information in the presentation tool 400a. Many POP3 proxy servers 100a automatically check the latest online spam blocking filter version on the designated remote server or access the remote server 400 at regular intervals and compare it with the online spam blocking filter version held by MUA. If there is an update, download a new version of the online spam filter to your MUA. The version comparison of the online spam blocking filter can be checked at regular intervals or by logging in to a certain remote server when the MUA restarts.

4 is a block diagram showing the configuration of an online spam blocking filter. The online spam blocking filter is a spam mail blocking list based on the statistical classification method and the number of hits based on the spam information DB. Spammer list (500a) including URL information and email address list for harmful sites, Contents filter list (500b) statistically applied, junk mail filter (500c) for detecting mail that does not comply with Internet protocols Characterized in that configured.

The online spam blocking filter includes a method that is regarded as a spam mail when the mail is not in accordance with the Internet rules, that is, the sender and the receiver are not specified or there are no subjects. The mail text filter is characterized in that simple text and HTML (Hyper Text Markup Language) statements can be checked at the same time to search for adult pictures.

5 is a block diagram for explaining a part excluding a remote server in the spam mail blocking system in the present invention. That is, the present invention provides a method for detecting, classifying and managing spam mails. Pop3 Proxy server 100a interworking with MUA for mail received from mail server detects and detects spam mail, stores it in IMAP server (100b), and checks the spam mail in MUA that supports IMAP protocol. Provide a technical approach. Before the MUA 100c receives the mail from the mail server 200, the proxy server 100a of the spam blocking system first checks the mail contents. The inspection criteria of the spam mail applied at this time may be an online spam blocking filter, a personal spam blocking filter, and an address book included in the MUA. Of course, the combination of these can be judged spam. At this time, the mail detected as spam mail / junk mail is delivered to the IMAP server 100b of the spam blocking system and stored. The undetected mails, that is, mails determined to be normal mails, are delivered directly from the POP3 Proxy server 100a to the MUA 100c. The MUA then accesses an IMAP server and looks up and manages spam. Through this process, normal mail and spam mail are completely detected, classified and managed on MUA. If you want to check the spam mail in the future to process normal mail directly on the MUA IMAP server (100b) to select the mail can be moved to the POP3 folder (100c) and vice versa. These mails are then processed as spam or normal mail. When using this method, drag & drop method is supported by linking with MAU so that users can use it conveniently when moving mail between POP3 and IMAP.

FIG. 6 is a flowchart of applying a criterion for checking spam mail in the POP3 proxy server described with reference to FIG. 4. When the mail is downloaded from the mail server 200, spam mail is first detected based on the online spam blocking filter (S2). The detected spam mail is stored in the spam mailbox (aa) corresponding to the IMAP server, and the undetected mail is moved and stored in the normal mailbox (bb). Each normal mailbox and spam mailbox correspond to the MUA 100c and the IMAP server 100b.

FIG. 7 shows a flowchart for blocking spam mail. FIG. 7 shows a spam detection criteria divided into two stages for detecting spam mail before being delivered from the POP3 Proxy server described in FIG. 4 to an IMAP folder or a POP3 folder. . When the mail is downloaded from the mail server 200, spam mail is first detected based on the address book information S1. That is, if a common mail address is not detected compared to the mail address recorded in the header information of the received mail based on the mail address book held by the MUA, it is considered as spam mail first and moved to the IMAP server 100b. Is saved. In the case of the second application criteria, the online spam blocking filter 405 is applied to the mail detected as spam mail (s2), and through this, the mail detected as a spam mail is completely spam (aa) and not detected. Is moved to the incomplete spam mailbox (cc) and stored. That is, the mailbox is divided into three types, namely, normal mailbox (bb), incomplete spam mailbox (cc), and complete spam mailbox (bb). Also, by checking the mail stored in the complete spam mailbox (aa) and incomplete spam mailbox (cc), the user can use the pass filter add function to prevent the mail from being processed as a spam mail in the future. It includes. In this case, the pass filter is a filter to apply a specific mail to select the mail to pass unconditionally without applying the online filter or address book information. Therefore, if the mail is stored in the incomplete spam mailbox (cc) or the complete spam mailbox (aa) to be processed later as a normal mail, it is characterized by including the process of registering the selected email address or domain address.

FIG. 8 illustrates a method for managing spam mails, particularly adult mails, so that they are not directly exposed to adolescents by setting access rights of mailboxes corresponding to IMAP servers and POP3 servers in MUA. When the user accesses the POP3 server, the boxes where normal mails are stored can be accessed by anyone without setting a password. However, when the user accesses the IMAP server, the user login process is required to access the relevant spam mailboxes (600).

In accordance with the present invention, the IMAP server provides a function for retrieving the mail by assigning a password to prevent the inquiry of spam mail and adult mail.

The present invention provides an advantage that can block spam mail through the online spam blocking filter. The advantage of the online spam blocking filter is that it is easy to use because it provides the filter list to the MUA connected to the Internet or network in real time, and the spam blocking effect is high because it is statistically analyzed and provided based on the actual spam information DB. . The infringement cases of personal information can be solved by granting the user the final authority such as determining the validity of the spam mail, deleting the spam mail, inquiring, or processing the normal mail for the spam mail filtered by the online spam blocking filter.

In addition, it provides users with the ability to sort, store, and encrypt spam mails with minimal settings, and allows them to selectively assign spam mail viewing and deletion functions according to the user's authority. To provide.

Therefore, the existing MUA can provide a system that can block spam mail without any user interaction.

Claims (6)

Statistical body of the message standards as defined by the (contents filtering) accepts offer online antispam filters from the remote server machine and the remote server system connected to the Internet Spam for online spam filter system for providing an online anti-spam filters store and distribute the provided filters Spam mail blocking system comprising a MUA system that can manage mail using POP3 Proxy method and IMAP method. The system of claim 1, wherein the online spam blocking filter providing system analyzes a DB system and a mail header information capable of periodically updating its information by receiving periodically updated information stored and stored in a commercial database or file system. It consists of spam filter for detecting mail_1 and spam filter for detecting spam mail_2 and spam filter for detecting junk mail_3 based on the contents of the mail body. Spam e-mail blocking system comprising an online spam blocking filter system to complement the spam filter _1 and spam filter _3 by applying the first method. The method of claim 2, wherein the spam filter_1 of the online spam blocking filter system includes a list collected based on mail sender address information, mail domain address information, mail sending date information, mail path information, and return-Path information. Spam filter_2 includes statistically collected lists to detect specific string inclusions, specific link inclusions, and specific character sets, and spam filter_3 includes email size restrictions, recipient and referrer restrictions, and attachment file size. A spam mail blocking system comprising a list for detecting spam mail through restriction. The online spam blocking filter of claim 1, wherein the online spam blocking filter is stored in a remote server system in which the online spam blocking filter is stored and a MUA connected through the Internet or a wired or wireless network to access the server to download the online spam blocking filter. Spam mail blocking system, characterized in that configured to automatically update to reflect the MUA. The MUA system classifies spam mail and normal mail using an online spam blocking filter provided from a remote server connected to the Internet or a network. Normal mail is spam mail blocking system, characterized in that configured to be stored in a general POP3 server. 6. The system of claim 5, wherein the mail regarded as spam stored in the IMAP server includes: a security method performing means for allowing only authorized users to input a password by applying a specific encryption method; Means for performing a feedback method having a function of later processing normal mail stored in a POP3 server as spam mail; Spam mail blocking, characterized in that it includes means for processing spam mail stored in the IMAP server later as normal mail and means for providing a delete cycle and automatic deletion function of spam mail for management of spam mail stored in the IMAP server. system.