Andrés ValenciaPC Security
This page offers information and tools to keep your PC secure,
- General Security Advice for Internet Users General Security Advice for Internet Users
The Internet is a dangerous environment as proven by the frequent "Denial of Service" attacks,
through "Worms" and "Trojan Horses",
infecting computers to implement "remotely controlled" intrusions in networks
by means of infected and enslaved PCs; "robots".
Your PC is not necessarily the final target in these attacks: If infected,
it is used to attack other computers and disseminate the infection.
The attempted dissemination activity congests the Internet, in particular e-mail transit.
A Web site knows the IP (Internet Protocol) address of the PC from where you are viewing it,
and could test your PC for vulnerabilities. If a vulnerability is found, the Web site could exploit it. If your PC has a vulnerability, and you visit a site that can exploit it, your PC could be enslaved. Backdoor and key-logger programs could be installed, or a remote attack on another computer be launched from your PC. If your Web browser has been infected by "Adware" so it makes automatic visits to unknown sites (pop-up advertising), its vulnerabilities could be exploited. See Spyware, further down in this page.
If you can not install and update a legal copy of MS Windows XP on an Internet-connected PC, it is possible that your vulnerabilities will be exploited even if you use a complete firewall program. Regularly update your Microsoft Office programs: visit Microsoft Office Online and select "Office Update", or visit Microsoft Update. Have your original MS Office installation disks on hand.
Microsoft Baseline Security Analyzer (MBSA) is free, but only available to legitimate Windows 2000, XP, 2003 o Vista users.
But if you must share files over the Internet, do not share whole drives;
only share expressly prepared, password-protected and "Read-only" folders with the required files.
Password-protected folders are available in Windows XP Professional.
In particular, never share the drive or the folder were the Operating System resides.
For example, create a folder named "Out" in "My Documents" and share it,
but do not check "Allow network users to change my files" (Properties, Sharing).
The Comodo Firewall Pro (Free) is also available, without the antivirus component.
If you want a simple firewall that is very easy to configure,
then you could use the Windows XP SP2 Internet Connection Firewall.
But if you want more advanced control over the traffic that passes through your computer
and you also want to block unauthorized outgoing traffic (traffic from your computer out to the Internet)
then choose a complete personal firewall from another company.
Visit a security evaluation site on the Web, such as Steve Gibson's
Gibson Research Corporation. Also run the tests for vulnerabilities to Internet threats at PC Flank (Make sure you're protected on all sides). Visit Secunia and SecurityFocus for Security News, Articles & Advisories. Visit the DeepSight Threat Management System from Symantec to learn the global level of the threats. Visit the site OnGuard Online of the U.S.A. Federal Government to read practical recommendations to help you be on guard against Internet fraud, secure your computer and protect your personal information.
The Web-based Security Scan and Virus Detection will help ensure a safe and productive Internet experience for you and your family. Security Scan determines whether your PC is protected from hackers, viruses, and privacy threats. Virus Detection uses Symantec's virus detection technology to check for virus infections. After analyzing your PC's current level of protection, we'll show you how you can enjoy the Internet and protect yourself at the same time. System Requirements:
Analyze your PC with the Trend Micro HouseCall AntiVirus - Scan Online: (Free) The Web-based HouseCall AntiVirus - Scan Online will help ensure a safe and productive Internet experience for you and your family. HouseCall uses Trend Micro's virus detection technology to check for and eliminate virus infections, spyware, worms and other malware. System Requirements:
Analyze your PC with the a-squared Online Malware Scanner: (Free) Analyze and clean your system with the a-squared Online Malware Scanner for Trojans, Backdoors, Worms, Dialers, Spyware/Adware, Keyloggers, Rootkits, Hacking Tools, Riskware and Tracking Cookies. Completely free, directly from your web browser. System Requirements:
Analyze your PC with the F-Secure Online Scanner: (Free) The Web-based F-Secure Online Virus Scanner will help ensure a safe and productive Internet experience for you and your family. The Online Virus Scanner uses F-Secure's virus detection technology to check for and eliminate virus infections and spyware. System Requirements:
Analyze your PC with the Panda Active Scan: (Free) Analyze your PC with the Panda Active Scan for Virus, Spyware, Hacking and Potentially Unwanted Tools, Dialers, Security Risks and Suspicious files (free analysis). Expanded Threats
Expanded Threats exist outside of commonly known definitions of viruses, worms, and Trojan horses
and may provide unauthorized access, and threats to system or data security,
and other types of threats or nuisances. Consider that an e-mail can show a faked sending (From:) address to gain your confidence and get you to execute an attached program or visit a link, believing it comes from a known address or person. See Symantec Security Response - Expanded Threats "Spyware" (Spy Software): "Spyware" programs are applications that send information via the Internet to the creator of the spyware, or the publisher. Spyware usually consists of core functionality and functionality for information gathering. The core functionality appeals to users and entices them to install and use the spyware. The End User License Agreement (EULA) informs users of the information-gathering actions, but most users overlook this information. Information that is sent to the publisher is normally used for improved direct marketing purposes. The type of sent information differs depending on the spyware program. In order for the publisher to properly digest the gathered data, some spyware programs send a unique identifier with the gathered information. Users often overlook the information-gathering functionality of spyware, leaving them unaware that the spyware publisher is gathering data from their computers. See The Dangers of Spyware in Symantec Security Response - White Papers (.pdf, Adobe Acrobat Reader).
Generally, if your Web browser has been infected by "Adware" (advertisement software, a type of "Spyware"), it will make automatic visits to unknown sites (pop-up advertising), and its vulnerabilities could be exploited. "Spyware" is a relatively new kind of threat that many common antivirus applications do not cover well. More and more spyware is emerging that is silently tracking your surfing behavior to create a marketing profile of you that will be sold to advertisement companies and used to force your browser to visit unknown sites automatically. See Symantec Security Response - Expanded Threats (Spyware)
Times have changed considerably and Symantec's approach to what were once referred to as expanded threats has evolved to meet the challenges posed by programs that are now broadly referred to as spyware. See Symantec Enterprise Solutions - Symantec's Antispyware Approach
You can get rid of much of the Spyware/Adware in your PC by using:
Ad-Aware Free detects and eliminates the intrusions already occurred and residing in your PC.
The above tools will help you to get rid of "Tracking Cookies"
(Third Party Cookies that use personally identifiable information) stored in your PC,
but you should configure your browser to block them.
A cookie is not a program, it is a very small text file with information that a Web site can store in your PC. A persistent cookie remains when you close your browser. A temporary or session cookie is stored only for your current browsing session, and is deleted from your computer when you close it. First-party cookies originate on or are sent to the Web site you are currently viewing. If you do not allow first-party cookies, you may not be able to view some Web sites or take advantage of their customization features. Third-party cookies either originate on or are sent to Web sites different from the one you are currently viewing. Third-party Web sites usually provide some content on the Web site you are viewing. For example, a site may use advertising from third-party Web sites and those third-party Web sites may use cookies. A common use for this type of cookie is to track your Web visits for advertising or other marketing purposes. Third-party cookies can either be persistent or temporary. A Web site only has access to the personally identifiable information that you provide to it, such as your log-in and preferences when visiting that site. Normally, only the Web site that created a cookie can read it. Your Internet Service Provider (ISP) assigns your PC an IP (Internet Protocol) address when you make a connection. An IP address is unique in the whole world at any time, and only your ISP can associate it with your PC at a particular time.
These are small malicious programs that connect over a telephone line a PC to a Dial-Up Network (DUN) at very high rates of cost to the user. In general it is required to examine your PC with an updated antivirus program to detect and eliminate them. Some can be detected by a user by examining "Internet Connections" in the Windows Control Panel. Malicious dialers are generally installed in your PC by visiting an infecting Website or by a new kind of virus that has one as a payload. You can eliminate malicious dialers from your PC with the a-squared Anti-Dialer Freeware! - free of charge Dialer scanner and remover. See Symantec Security Response - Expanded Threats (Dialers)
A rootkit is a component that uses stealth to maintain a persistent and undetectable presence on the machine. Actions performed by a rootkit, such as installation and any form of code execution, are done without end user consent or knowledge.
Rootkits do not infect machines by themselves like viruses or worms,
but rather, seek to provide an undetectable environment for malicious code to execute.
To manually install rootkits,
attackers will typically leverage vulnerabilities in the target machine, or use social engineering techniques. Once installed, an attacker can perform virtually any function on the system to include remote access, eavesdropping, as well as hide processes, files, registry keys and communication channels. A good antivirus program, like the AVG Anti-Virus Free Edition from Grisoft, or the a-squared Free, should detect a rootkit not yet installed. To detect and eliminate one that has been able to install, you can use the Sophos Anti-Rootkit, or the Trend Micro RootkitBuster (Free).
See
Rootkits - A New Malware Trend
(a2 Knowledgebase, EMSI Software)
Malicious scripting attacks are a threat to Web users. A Web site can use a scripting language, like JavaScript, to exploit security vulnerabilities that could allow it to perform installations of spyware or remote control programs.
Firefox, Internet Explorer 7 and Opera have some features to prevent these exploits,
including pop-up warnings that let the user know when a Web site uses scripting.
But these all/nothing controls are not flexible enough.
Cross-site scripting (XSS) attacks occur when an attacker uses a Web application to send malicious code, generally in the form of a browser side script, to a different end user. Flaws that allow these attacks to succeed are quite widespread and occur anywhere a Web application uses input from a user in the output it generates without validating or encoding it. An attacker can use XSS to send malicious script to an unsuspecting user. The end user's browser has no way to know that the script should not be trusted, and will execute the script. Because it thinks the script came from a trusted source, the malicious script can access any cookies, session tokens, or other sensitive information retained by your browser and used with that site. These scripts can even rewrite the content of the HTML page. See Cross Site Scripting Open Web Application Security Project (OWASP) See Cross-site scripting Wikipedia, the free encyclopedia
None of the solutions that Web users can take are complete solutions. In the end, it is up to Web page developers to modify their pages to eliminate these types of problems.
However, Web users have two basic options to reduce their risk of being attacked through this vulnerability.
The first, disabling scripting languages in their browser,
provides the most protection but has the side effect for many users of disabling functionality that is important to them.
Users should select this option when they require the lowest possible level of risk. See Malicious HTML Tags Embedded in Client Web Requests CERT Advisory CA-2000-02
A Final Warning
Attackers are moving away from large, multipurpose attacks on network perimeters and towards smaller,
more focused attacks on desktop computers. See Symantec Enterprise Solutions - Internet Security Threat Report
One of the most successful "botnets" of 2007 has been "Storm". The Storm botnet, estimated now to contain millions of compromised computers, has advanced defenses. See Cracking open the cybercrime economy (Tech News on ZDNet, Dec 14, 2007)
Malware is no longer being built for self promotion purposes, or for fun,
but rather with the primary aim of earning large amounts of money.
Spammers use this computing power to anonymously send millions of e-mails.
Other shadowy organizations use the storage capacity to store and distribute illegal data,
such as child pornography or similar. See Malware Annual Report 2007 (Emsi Software, 1/17/2008)
They normally ask you to unknowingly navigate to a spoofed Web site (with a false URL) to provide, update or confirm sensitive personal information. To attract you, they may refer to an urgent situation in your account or a very interesting offer.
Some information that Phishing scams are after: Even if you don't provide what they ask for, simply clicking on the link could subject you to "silent" installations of key logging software or backdoor programs. Many of these sites open spoofing windows to obtain your authorization for an installation. Close them using the X in the upper-right corner of the window. Do not use the controls in these windows; a button can do anything, no matter how it is marked. Consider that a Web page can spoof the contents of both the Address (URL) and Status Bar.
When OpenDNS is unable to determine how to resolve a URL (for example, a typo which is not in our "errors we can fix" list), then OpenDNS provides search results that are the best match for the information provided.
Here's a quick way to tell if your DNS servers are at risk:
If your DNS server appears safe, you should get:
Multiple DNS implementations vulnerable to cache poisoning:
OpenDNS is proud to announce that they are one of the two DNS vendors / service providers
that were not vulnerable when this issue was first discovered by Dan Kaminsky. More news will be coming about this DNS vulnerability, and a major anouncement by Kaminsky is expected in August 6 '08 during the Black Hat conference in Las Vegas.
Akamai [a global server network that handles 20% of the world's total Web traffic] on Thursday [May 29 '08] released its first State of the Internet report and found attack traffic – viruses, worms, bots and such – derived from 125 countries, with 30% of that traffic coming from the United States and China. Some of these attacks, which occurred in the first quarter, were from worms like the Blaster back in 2003. Of that attack traffic, the top 10 countries accounted for 75% of the attacks. The surprising hotspots for attacks included Venezuela, Argentina and Brazil – three places not exactly known for their hacking communities. Russia was a no-show.
Here's the chart from Akamai's report, which requires registration:
My specialty is Personal Computing and I work as an independent consultant.
Updated: November 18 '08 Symantec and Trend Micro Security Alerts Boxes Castellano: Sección sobre Seguridad de PCs Back: Home Page (PC Security and Updating Service) Messages: Andrés Valencia: Communications |