双重扫描保安全——风险评估应采用基于主机与基于网络并行的方式

从信息安全的角度看,风险评估(Vulnerability Assessment)是网络安全防御中的一项重要技术,其原理是通过对目标可能存在的已知安全漏洞进行逐项检查。目标可以是工作站、服务器、交换机、数据库应用等各种对象,然后根据扫描结果向系统管理员提供周密可靠的安全性分析报告,从而为提高网络安全整体水平产生重要依据。其中,网络安全扫描工具已成为风险评估的主要手段。而网络安全扫描工具因为其安装的环境     

用扫描工具加强校园网的安全

校园网的广泛使用为学校教育信息化铺平了道路,同时信息安全问题也日益突出,黑客和恶意代码正不断威胁着校园网的安全。本文首先介绍了扫描工具及其功能,通过扫描工具在校园网上的应用实例说明扫描工具可以加强校园网络安全。     

网络安全漏洞扫描技术研究

安全漏洞扫描技术是一种逐渐成熟的维护网络安全的重要工具,文章说明了网络安全漏洞扫描的必要性,概述了漏洞扫描的技术和方法,提出网络漏洞扫描系统的设计目标和原则,并以此设计出工作模型,最后介绍了安全漏洞扫描技术的发展趋势。     

利用Windows XP漏洞入侵计算机

笔者是单位的网络管理员,现在各级网络安全部门的各种文件均要求加强网络安全管理,然而网络安全的问题单单只靠网络管理员一个人是解决不了问题的。微软最近发布的几个漏洞,如:MicrosoftWorkstation服务允许任意代码攻击漏洞,于是上网重新下载了一个带ms03049漏洞扫描插件的X-scan扫描工具重新对网络进行扫描,发现一些机器存在着这些漏洞。     

网络扫描技术实现及其在网络安全中的应用

在介绍了网络扫描器和其基本工作原理后，归纳并且详细分析了网络安全扫描软件所涉及到的几种关键技术，其中包括：全TCP连接扫描、TCP SYN扫描、ICMP扫描、TCP FIN扫描等。然后介绍了几种常见的端口扫描工具以及网络安全扫描软件：Safety。最后给出了解决端口扫描问题的建议和对策。     

Webprobe:自验证的Web服务安全探测工具

为了有效解决现存网络安全扫描工具中普遍存在的高误判率问题，提出了基于试探攻击和漏洞验证来评估Web服务安全的方法，描述了一个用该方法实现的Web服务安全探测工具——Webprobe，对比和讨论了现存Web服务器扫描软件的判断不准确的问题。实验证明，这种自验证方法可以大大降低误判率，提高网络安全管理人员的工作效率。     

企业级弱点评估管理系统

Foundstone Enterprise RiskSolution企业级弱点评估管理系统,采用仿真黑客行为模式的人工智能扫描技术,针对暴露在网络上的主机与网络服务信息进行扫描分析,有效祢补一般网络安全扫描工具的缺点与被忽略的问题。     

“流光”解限大行动

“流光”是一款大名鼎鼎的网络安全扫描工具，它由知名的网络安全专家小榕开发。它可以探测POP3、FTP、HTTP、PROXY、FORM、SQL和SMTP上的各种漏洞，可以让初学者快速地掌握网络安全相关的操作能力。     

漏洞扫描技术及其在入侵检测系统中的应用

介绍了漏洞扫描器和其基本工作原理后,归纳并且详细分析了网络安全扫描软件所涉及到的几种关键技术.其中包括全TCP连接扫描,TCPSYN扫描,ICMP扫描和TCPFIN扫描等.然后介绍了几种常见的漏洞扫描工具,最后介绍了漏洞扫描技术在入侵检测系统中的具体应用和入侵检测系统的未来发展.     

网络安全漏洞扫描技术的原理与实现

网络安全漏洞扫描是网络安全体系中一种重要的防御技术。文章说明了两种网络安全漏洞扫描的原理，给出了网络安全漏洞扫描的体系结构。并在此基础上实现了一个基于网络安全的漏洞扫描系统。     

基于网络的漏洞扫描器设计与实现

近年来扫描器在计算机系统安全方面担当着重要的角色。扫描器的主要功能是检测系统有没有安全漏洞,进而生成安全漏洞报告给使用者。本文首先分析了基于网络的漏洞扫描器的概念和工作原理,然后给出了一个具体的漏洞扫描器的设计及实现技术。     

网络安全漏洞扫描器

网络安全漏洞扫描器是近年来网络安全研究的热点。文章说明了网络安全漏洞扫描的必要性,给出了网络安全漏洞扫描器的概念和结构,概述了多种漏洞扫描的技术,最后介绍了网络安全漏洞扫描器的国内外现状及评判标准。     

Scanner design

The scanner is a subroutine which is frequently called by an application program like a compiler. The primary function of a scanner is to combine characters from the input stream into recognizable units called tokens. A method has been presented in this paper for designing such a scanner, also frequently referred to as a lexical analyser in the current literature. The major steps involved in this design process are: identification of tokens, construction of a state diagram, building driver tables and finally writing a scanning routine. The rules for generating the driver tables are described and an algorithm for the scanner, utilizing these driver tables, is included. The method has been successfully used to build the system scanner for a user oriented plotting language. It is concluded that the method is well defined, gives rise to a modular design and as such easily lends itself to language extensions.     

基于SANE标准的光栅扫描设备应用程序的开发

本文介绍了光栅扫描设备应用程序的开发标准SANE，以及如何基于SANE 标准开发扫描设备的应用程序。     

基于Fusion FPGA无刷直流电机的控制器设计

微波成像扫描仪是气象卫星上的重要酬载,扫描仪的控制系统是扫描仪上的核心机构,其控制性能将对扫描仪的成像精度和卫星任务的完成情况产生重大影响。采用Actel StartKit FPGA开发板为微波成像扫描仪内的无刷直流电机设计了控制器,详细介绍了控制器中各模块的设计,包括PWM波发生、换相控制、以及双闭环增量式数字PID调节等模块。基于SoPC的设计思想,使得系统模块都集成在一片FPGA上,提高了系统的可靠性和稳定性。软件仿真和实验结果表明,设计的控制器精度高,运行稳定。     

Dynamic characterization and modification of dynamic properties of a micro scanner

Micro electro mechanical systems (MEMS) are used in many application areas in different disciplines and took their place among the most promising technologies. The performance of such systems is primarily related to their dynamical characteristics. This study presents the dynamic characterization techniques that are used to identify the modal parameters of a MEMS device and the methods that can be implemented to change its dynamic response. An electrostatic scanner is chosen as the case study to demonstrate the developed methodologies. Initially, the micro scanner is characterized using experimental modal analysis techniques to obtain frequency response function, modal damping, resonance frequencies, and mode shapes. Then, velocity and position feedback control loops are implemented to the scanner system to alter the damping and stiffness characteristics. A closed-loop Simulink model of the scanner is developed to verify the experimental measurements. Several curve fitting methods are used in order to have an accurate representation of the scanner system. Using the model, the influence of both position and velocity feedback on the effective damping, resonance frequency and the transient behavior of the scanner is investigated. The stability limits of the scanner under velocity feedback are also studied via numerical simulations. Based on the experimental and simulation results, the methodology developed in this study proves itself to be very efficient to alter the dynamical characteristics of the MEMS structures and it can be easily adapted to other MEMS applications.     

脱机掌上扫描仪的设计

提出了一种脱机掌上扫描仪的体系结构，完成了脱机掌上扫描仪硬件系统的设计，重点讨论了CIS系统和同步机构的硬件实现，为脱机掌上扫描仪的研制解决了技术难题。同时，给出了脱机掌上扫描仪软件系统框图，最后对设计的脱机掌上扫描仪进行了测试，并对测试结果进行了分析。     

Electromagnetic Two-Dimensional Scanner Using Radial Magnetic Field

In this paper, we present the design, fabrication, and measurement results of a two-dimensional electromagnetic scanning micromirror actuated by radial magnetic field. The scanner is realized by combining a gimbaled single-crystal-silicon micromirror with a single turn electroplated metal coil, with a concentric permanent magnet assembly composed of two concentric permanent magnets and an iron yoke. The proposed scanner utilizes the radial magnetic field rather than using a lateral magnetic field oriented 45deg to the horizontal and vertical scan axes to achieve a biaxial magnetic actuation. The single turn coil fabricated with electroplated copper achieves a nominal resistance of 1.2 Omega. A two-dimensional scanner with mirror size of 1.5 mm in diameter was fabricated. Maximum optical scan angle of 8.8deg in horizontal direction and 8.3deg in vertical direction were achieved. Forced actuation of the gimbal at 60 Hz and resonant actuation of the micromirror at 19.1-19.7 kHz provide slow vertical scan and fast horizontal scan, respectively. The proposed scanner can be used in raster scanning laser display systems and other scanner applications.     

Experimental identification of abnormal noise and vibration in a high-speed polygon mirror scanner motor due to mechanical contact of plain journal bearing

This paper investigates the abnormal noise and mechanical vibration of a high-speed polygon mirror scanner motor due to the mechanical contact between the rotating shaft and stationary sleeve. In the paper, we analyze the characteristics of the aerodynamic noise, structural borne noise, and electromagnetic noise in a polygon mirror scanner motor. We determine the characteristics of the main harmonics of structural borne noise by analyzing the correlation between sound and vibration and by evaluating the effect of specific harmonics on sound quality. We also develop an experimental set-up to measure the mechanical contact and the mechanical vibration of the polygon mirror scanner motor simultaneously. This paper uses the experimental setup to show that the mechanical contact between the rotating shaft and stationary sleeve is one of the dominant sources of the vibration that generates the abnormal noise of the high-speed polygon mirror scanner motor.     

安全扫描器综述

安全扫描器是自动检测远端或本地网络和主机安全脆弱点的软件。文章介绍了安全扫描器的概念、功能、分类、体系结构、原理及软件结构，概述了当前安全扫描器采用的技术，同时分析两类安全扫描器的实现，并比较了它们的特性，分析了影响扫描器的因素，并由此指出了扫描器的发展趋势。