ep6network | Network security

Network security, Security softwares,wifi security, wireless security


At first welcome to my Network Security forum. Here you can find all the security features of a network and Operating system also. In this blog you will find the best notes. I tried to simplify and descriptive those notes. You can find here different types of Adware and Spyware threats and their prevention, definition of Different types virus and procedure their cure, Antivirus and some link of free antivirus, spy cure, adware cure etc. we can also learn here How to secure telephone network, Large area network (LAN), Wide area network. Here I have provided the trick of Firewall, The architecture of a network, Cryptography, Internet Key exchange, IP security, Crypto History, Cryptography Blocks and many more which will help you to further study. And this is not the end Keep visited this blog and I will provide you more a more security tricks. And don’t forget to comments on that if it is bad or good. Please do comment on my thesis. Your comments will help me to upgrade my thesis. And if you want some exact notes on some security tricks. Please do inform me. My email id is ep6secuirity@gmail.com I will try to do my best, if I will not be able to fulfill your requirements, I will make you inform.

Thanks and Regards

Utsav Basu

For – ep6network.


Your Ad Here

Catching Scan Signatures

As an administrator, you should be running vulnerability scanners against your web servers as part of routine maintenance. After all, it would be best to find your own vulnerabilities before someone else does. On the other hand, how can you tell if someone is running these tools against you? An intrusion detection system (IDS) can help, but an IDS has several drawbacks: it typically cannot handle high bandwidth, it relies on pattern-matching intelligence, it cannot (for the most part) watch encrypted SSL streams, and it is expensive (even the open-source snort requires a team to maintain and monitor events). The answer, in this case, is to turn to your logfiles. You enabled robust logging for your web server, right?

Common Signatures Logfiles are a security device. They are reactionary, meaning that if you see an attack signature in your file, you know you've already been attacked. If the attack compromised the server, web logs will be the first place to go for re-creating the event. Logs also help administrators and programmers track down bugs or bad pages on a web site—necessary to maintain a stable web server. With this in mind, you should have a policy for turning on the web server's logging, collecting the logfiles, reviewing the logfiles, and archiving the logfiles.

The following table lists several items to look for when performing a log review. Many of these checks can be automated with simple tools such as grep.


Stealth is a vulnerability scanning tool created by Felipe Moniz. It uses the Windows GUI and therefore doesn’t have the cross-platform capability of nikto. Stealth’s strength lies in its number of checks and, like nikto, ease of updating its database. More than 13,000 checks currently populate the Stealth database, although only about 5000 of them are unique. These checks range from URLs that break obscure devices with embedded web servers to the most current IIS vulnerabilities.


By Default, Stealth uses the “normal” Scan Rule, which contains roughly 6500 checks. This screen is accessed by clicking the Scanner button in the Stealth application window

Stealth can also scan a range of web servers. However, range must be a list of sequential IP addresses. It is not possible to load a custom list of target IP addresses. This slows down scans that target a network, because Stealth must first identify a web server before scanning it. When servers are distributed across networks, this is even slower.

One more note about scanning a range: Any time Stealth encounters an error, it pops up a message box that requires manual intervention to close. In short, Stealth is not the best tool for scanning multiple servers at once.

The IDS Test button works much like nikto’s IDS evasion techniques. Stealth offers 13 different evasion techniques. Select which techniques you want to use, and then choose CGI Setup | Use IDS Evasion.

When Stealth finishes a scan, it prompts the user to save the report. A Stealth report is an HTML file that lists any potential vulnerability it discovered. This is a quick, straightforward tool that assumes you want to run 6500 checks against a web server every time.

Creating New Rules

Rule construction for Stealth is simple. You specify the URL, the request method, and the expected HTTP return code. For example, to look for a backup index.html file, you would create a file with these contents:

#INF Backup index.html file
#GET /index.html.bak #200

The #GET method could also be #HEAD or #POST. The #200 return code can be any HTTP response. Stealth does not use custom arrays, so files within a set of directories must be listed individually. Both #GET and #200 are assumed by default and can be omitted. Thus, the basic URL checking of Stealth is not as robust as whisker. Stealth does try to simplify the vulnerability development process with its Stealth Exploit Development Tool.

The Exploit Development Tool is a GUI utility that prompts you for each of the possible fields that can be created for a vulnerability check.

The Options tab is where you specify a string that would indicate the check returned a false positive or specify a User-Agent. Some web applications rely on the User-Agent header for determining whether a browser can access the site. Some browsers do not support JavaScript, ActiveX, or Java that would cause the application to disallow access.

Another cool Stealth technique is the buffer overflow test. A buffer overflow attack can be crafted against any URL in a web application that has a parameter list. The Stealth rule for a buffer overflow has four components:

  • bofgen The URL, encased in double-quotation marks.

  • bofstr A placeholder for the buffer overflow string. The bofstr value is replaced by the actual attack.

  • bytes The number of times to repeat the buffer overflow character.

  • chars The buffer overflow character.

For example, here’s the rule to check for a buffer overflow condition in a web application’s login page:

#INF Login.asp buffer overflow check.

Pitfalls to Avoid

As mentioned, Stealth’s ability to scan a range of web servers automatically is severely limited. Stealth occasionally generates DNS errors, which usually happens when scanning a server with virtual hosts or when it scans a server with multiple IP addresses (as is the case for many large, load-balanced sites). A DNS error is innocuous, but it requires that you close the pop-up message box Stealth generates.

The majority of Stealth’s checks rely on the HTTP return code from the server. This is useful when you’re checking for the existence of a vulnerable script, but it does not necessarily indicate that a script is vulnerable. For example, many of the viewcode.asp vulnerabilities in IIS sample files have been fixed in recent updates, but Stealth merely checks for their presence and often produces false positives. Even though Stealth can parse the output of a check for a specific string, few of the checks seem to do so. Relying on the HTTP return code doesn’t mean that Stealth will miss vulnerabilities, but it does mean that it will produce a large number of false positives.

A GUI-based tool does not play well with others. It is difficult to create a script that generates a list of web servers or systems with port 80 open, input that list to Stealth, and then perform some file parsing on Stealth’s output. A command-line tool, on the other hand, doesn’t mind being wrapped in FOR loops and having data piped into it from other programs or sending its output to your favorite parsing tool. Remember the ease with which we manipulated the output from whisker with the tee and grep commands?

Finally, Stealth cannot handle SSL connections. This is a simple drawback to overcome.


In the HTTP request that Stealth sends, the %bofstr string is replaced by 999 As.

Once any exploit is created, you must still instruct Stealth to use it. If you place the file in the Db subdirectory of the Stealth installation directory, Stealth will find the exploit and load it. To check this manually, or to create a new exploit, click the Database button in the Stealth application window and select the Stealth User’s Exploits tab.


Post a Comment

Promote my blog from
Technology Visit blogadda.com to discover Indian blogs Top Blogs
blogarama - the blog directory blog directory Blogs lists and reviews Blog Ratings Show off your blog
My Zimbio Webfeed (RSS/ATOM/RDF) submitted to http://www.feeds4all.nl TopOfBlogs GoLedy.com Best Indian websites ranking Technology (Gadgets) - TOP.ORG
Free Blog Directory Internet blogs Webfeed (RSS/ATOM/RDF) submitted to http://www.feeds4all.nl