SMTP Session Probing for Spam Bot Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current spam detection methods are ineffective in identifying and neutralizing spam bots, which cause significant strain on email servers and result in false positives, as they primarily focus on post-delivery filtering rather than real-time analysis and do not adequately address the root cause of spamming activities.

Innovation Solution

A system that analyzes client programs' interactions with data transmission protocols to recognize and block spam bots by introducing irregularities and monitoring responses, using a database of reputability rules to assess the likelihood of spamming activity and implement counter-measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If post-delivery filtering is used to detect spam, then spam messages can be identified after delivery, but false positives occur and the root cause of spamming is not addressed

Engineering Contradiction:
Improvespam detection accuracyVSAvoidfalse positive rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by analyzing client behavior during the SMTP communication session before spam messages are fully delivered. The system probes the client program's responses to server requests and irregularities introduced during the data transmission phase, enabling early identification of spam bots before they can send large volumes of spam, thus reducing both false positives and the root cause of spamming.

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If traditional filtering mechanisms are used, then spam can be identified by keywords or blacklists, but they cannot detect spam bots at the source

Engineering Contradiction:
Improvespam traffic volumeVSAvoidspam bot identification capability
Core Design Contradiction:
Object-generated harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces an intermediary probing mechanism that acts as a mediator between the mail server and the client program. The session handler module introduces controlled irregularities into the SMTP protocol exchange and monitors the client's responses, enabling detection of spam bots at the source by analyzing their implementation deficiencies without requiring complex filtering mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies self-service by exploiting the spam bot's own poor implementation and vulnerabilities in its SMTP client code. By introducing irregularities that reveal these deficiencies, the system enables the mail server to automatically identify and block spam bots without external assistance, turning the spam bot's weaknesses against itself.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If spam bots are allowed to operate, then email services remain accessible, but server strain increases significantly

Engineering Contradiction:
Improveemail service availabilityVSAvoidserver load from spam traffic
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The system performs preliminary identification and blocking of spam bots during the initial SMTP session establishment phase, before spam messages are sent. By analyzing the client's response to probed irregularities in real-time, the server can prevent spam traffic generation while maintaining normal email services for legitimate clients, thus reducing server strain without compromising service availability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2490383B1Systems and methods of probing data transmissions for detecting spam bots
Publication Date: 2014.08.27 AO KASPERSKY LAB
  • EP2490383B1 patent drawingFigure 1A~1B
  • EP2490383B1 patent drawingFigure 1C
  • EP2490383B1 patent drawingFigure 2

AI summary

A computer-implemented system and method for detecting, by a mail server module, spam bot activity by a client device. An email session is conducted between the mail server module and the client device according to a predetermined protocol that includes exchange of messages between the mail server module and the client device. The mail server module probes compliance with the predetermined protocol including: purposefully introducing at least one irregularity into a first message from the mail server module; monitoring a subsequent message transmission from the client device; comparing the subsequent message against reference criteria; and producing a reputability determination for the client device based on an extent to which the subsequent message was a proper response to the at least one irregularity according to the predetermined protocol, the reputability determination being indicative of a likelihood that the client device conducts spam bot activity.