Security Corner

March 31, 2009  12:48 AM

What Will Conficker do on April First?

Ken Harthun Ken Harthun Profile: Ken Harthun

No one knows for sure, but we do know that *something* is going to happen on April Fools’ Day. Conficker is a new breed of malware; the people behind it are of exceptional intelligence. They aren’t a crew of script kiddies out to make a quick buck. Whatever Conficker is specifically designed to do, you can bet its actions will be directed toward: 1. Maximizing proliferation of its binaries (survival); 2. Avoiding detection; and, 3. Maximizing profit (or damage).

The worm has been pretty effective at #1, by some estimates having already infected several million PCs. It has done this through exploitation of a Windows vulnerability, MS08-067 that was patched back in October and about which I wrote Will They Ever Learn to Patch? in January. However, it’s possible that those computers in the most concentrated areas of infection–China, Russia, India, Brazil, and Argentina–are impossible to patch because they are running pirated copies of Microsoft Windows software, and Microsoft does not allow updates of any kind to its pirated software. Seems to me this is a self-defeating policy, but I’m just a sensible Geek, not a Microsoft executive.

As for #2, the latest variant has added new anti-detection features. According to Larry Seltzer writing in, “Avoiding detection is a major theme with Conficker.C. It’s not the first malware to try to defend itself in-memory against security software and diagnostic tools, but “C” does a lot of this. For instance, it disables Windows Automatic Updates and the Windows Security Center.”

We’ll find out Wednesday, April 1st, what–if anything–happens with #3. My bet is that it’ll be another Y2K-type event. Then again, who knows?

March 27, 2009  5:32 PM

NoScript Blocks Latest Firefox Bug

Ken Harthun Ken Harthun Profile: Ken Harthun

Got NoScript? If not, get it–the latest Firefox bug, an XML tag remote memory corruption vulnerability released on Wednesday, is mitigated by having the NoScript addon installed.

The bug can be exploited by a malicious website and can cause the browser to execute malware with no user intervention. All 3.0.x versions of Firefox running on Windows, Mac, and Linux operatintg systems are vulnerable. According to the Mozilla Wiki, the patched version, Firefox 3.0.8, “…is a high-priority firedrill security update to Firefox 3.0.x” and will be rolled out April 1.

The 3.0.8 release also fixes the Pwn2Own bug discovered at CanSecWest 2009, an issue that NoScript also mitigates.

I’ve said it before (see “Software for Secure Computing: Firefox & NoScript“); now’s a good time to say it again: install NoScript, and enjoy secure computing.

SecurityFocus bulletin:
The Register article:
Mozilla Security Blog post:

March 25, 2009  1:49 PM

Worm Targets Home Networking Equipment

Ken Harthun Ken Harthun Profile: Ken Harthun

As reported yesterday in The Register, the “psyb0t” worm targets home routers and modems and may be the first piece of malware to do so. Researchers from DroneBL, a real-time tracker of abusable IPs, say that as of March 22 100,000 hosts had been infected.

Whether or not your equipment is vulnerable depends on three things:

  • Your device is a mipsel (MIPS running in little-endian mode, this is what the worm is compiled for) device.
  • Your device also has telnet, SSH or web-based interfaces available to the WAN, and
  • Your username and password combinations are weak, OR the daemons that your firmware uses are exploitable.

“This technique is one to be extremely concerned about,” the researchers say, “because most end users will not know their network has been hacked, or that their router is exploited. This means that in the future, this could be an attack vector for the theft of personally identifying information.”

If you believe your equipment is vulnerable or has been compromised, you should immediately take the following actions:

  1. Power cycle your router.
  2. Disable WAN-facing telnet, SSH or web-based configuration interfaces.
  3. Change the passwords to something unguessable (see this article).
  4. Upgrade to the latest firmware.

March 24, 2009  6:47 PM

Pagefile.sys is a Security Risk

Ken Harthun Ken Harthun Profile: Ken Harthun

Since the early days of Windows (3.x and forward), the operating system has relied upon vritual memory in the form of files stored on the hard drive to compensate for the lack of a machine’s physical memory. When the machine’s physical memory begins filling up, pages of data are moved from physical memory to the virtual memory file. Until Windows NT, this file was called win386.swp; when NT came along, it was renamed to pagefile.sys. While the pagefile generally enhances performance, it’s a security risk.

For one thing, Windows’ default behavior leaves the pagefile intact when a user logs out, so there’s a good chance of viewing information in any files the user opened while logged in.

Encryption doesn’t necessarily mean the data is safe, either. Sure, the file itself is encrypted, but in order to work with encrypted files, the system must first decrypt them and this unencrypted copy may be stored in the pagefile.

There’s a simple registry setting that will clear your pagefile when you shutdown your computer. Why this setting isn’t enabled by default only makes sense from a performance standpoint. It may take Windows slightly longer to shut down, but you’ll rest easier knowing your confidential data isn’t at risk.

Start regedit and navigate to:


Set the key ClearPageFileAtShutdown to 1

Close regedit and reboot your computer to apply the change.

March 20, 2009  1:35 AM

Another Little Known Tool to Securely Delete Files, Folders, and Volumes

Ken Harthun Ken Harthun Profile: Ken Harthun

Why, all of a sudden, is everyone concerned about secure file deletion? I hesitate to say it’s a sign of the poor economy, but perhaps people consider it even more important to protect their personal information when the idea of losing control of their assets—and their lives–through the incompetence of corporate “managers” and well-intentioned but clueless politicians is more abhorrent than losing control through the outright thievery of Internet gangs. It’s weird. I harped on people about securing their data all along and mostly, my advice fell on deaf ears. Now people are worried. And it’s not because they see more spam email phishing attempts, it’s because they feel they can’t trust anyone anymore, not their formerly respected captains of industry, and certainly not their elected officials.

But, I digress. This post is about security tools, not politics, so I’m now officially off of my soapbox.

I recently posted an article about SDelete, a tool that can be used to securely delete files and folders on a hard drive. There’s another little known, useful tool that has been built into the OS since Windows 2000: cipher.exe. Microsoft provides the following in Knowledge Base article 315672:

How to Use the Cipher Security Tool to Overwrite Deleted Data

To overwrite deleted data on a volume by using Cipher.exe, use the /w switch with the cipher command. Use the following steps:

  1. Quit all programs.
  2. Click Start, click Run, type cmd, and then press ENTER.
  3. Type cipher /w:driveletter:\foldername, and then press ENTER. Specify the drive and the folder that identifies the volume that contains the deleted data that you want to overwrite. Data that is not allocated to files or folders will be overwritten. This permanently removes the data. This can take a long time if you are overwriting a large space.

One more tool you can use to mollify your paranoid clients.

March 20, 2009  12:31 AM

Win an Xbox for Asking & Answering IT Questions

Ken Harthun Ken Harthun Profile: Ken Harthun

Hey, fellow Geeks,

Now through the end of April, your tech savvy can earn you the chance to win one of three Xbox 360 game consoles being given away by our favorite tech site, IT Knowledge Exchange. Winners will be the top three community members who have the most Knowledge Points earned and have asked five IT-related questions. You still get points for asking other questions, but only those related to IT will be counted for the contest. Full details are in community manager’s Jenny Mackintosh’s ITKE Community blog posting, so go there for rules, etc.

The three winners will receive:

  • First Place: Xbox 360 Elite
  • Second Place: Xbox 360
  • Third Place: Xbox 360 Arcade

This is a chance to show off your IT guru skills and win a neat prize in the process. Go ahead and ask a tough question (remember, you need to ask five of them) by going to the Ask a Question page.

Good luck and have fun!

March 16, 2009  5:41 PM

RSA Social Security Awards: Please Nominate Security Corner

Ken Harthun Ken Harthun Profile: Ken Harthun

If you like Security Corner and find it useful, I would appreciate your nomination. I suppose the best category would be the non-technical blog. Here’s info from their blog post:

The nominations for the Social Security Awards are well underway and we currently have more than 450 nominations in hand. People can keep nominating until March 31 at which time we will sift threw the nominations and hand over the final five in each category to our esteemed panel of judges from CSO Magazine, Washington Post, Forrester Research, Dark Reading and TechTarget.

I want to clarify that you need not be present to win one of the Social Security Awards, so get your readers to nominate you in one of the following categories:

  • Best Security Podcast
  • Best Technical Security Blog
  • Best Corporate Security Blog
  • Best Non-Technical Security Blog
  • Most Entertaining Security  Blog

Thanks in advance for your show of support!


March 6, 2009  1:35 AM

Firefox 3.0.7 Released, Addresses Multiple Vulnerabilities

Ken Harthun Ken Harthun Profile: Ken Harthun

Mozilla Foundation released Firefox 3.0.7 today to address multiple vulnerabilities. According to the Security Advisories, the vulnerabilities may allow an attacker to execute arbitrary code, cause a denial-of-service condition, obtain sensitive information, or spoof the location bar. Mozilla says that the vulnerabilities also affect Thunderbird and SeaMonkey. No updates have been released for these applications at this time.

The following Security Advisories are addressed in Firefox 3.0.7:

  • Mozilla Foundation Security Advisory 2009-07: “Mozilla developers identified and fixed several stability bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these crashes showed evidence of memory corruption under certain circumstances and we presume that with enough effort at least some of these could be exploited to run arbitrary code.”
  • Mozilla Foundation Security Advisory 2009-08: “An anonymous researcher, via TippingPoint’s Zero Day Initiative program, reported a vulnerability in Mozilla’s garbage collection process. The vulnerability was caused by improper memory management of a set of cloned XUL DOM elements which were linked as a parent and child. After reloading the browser on a page with such linked elements, the browser would crash when attempting to access an object which was already destroyed. An attacker could use this crash to run arbitrary code on the victim’s computer.”
  • Mozilla Foundation Security Advisory 2009-09: “Mozilla security researcher Georgi Guninski reported that a website could use nsIRDFService and a cross-domain redirect to steal arbitrary XML data from another domain, a violation of the same-origin policy. This vulnerability could be used by a malicious website to steal private data from users authenticated to the redirected website.”
  • Mozilla Foundation Security Advisory 2009-10: “libpng maintainer Glenn Randers-Pehrson reported several memory safety hazards in PNG libraries used by Mozilla. These vulnerabilities could be used by a malicious website to crash a victim’s browser and potentially execute arbitrary code on their computer. libpng was upgraded to a version which contained fixes for these flaws.”
  • Mozilla Foundation Security Advisory 2009-11: “Mozilla contributor Masahiro Yamada reported that certain invisible control characters were being decoded when displayed in the location bar, resulting in fewer visible characters than were present in the actual location. An attacker could use this vulnerability to spoof the location bar and display a misleading URL for their malicious web page.”

Everyone should immediately upgrade to Firefox 3.0.7 to mitigate these issues.

February 28, 2009  4:11 PM

Use This Little Known Tool to Securely Delete Files and Folders on Your Hard Drive

Ken Harthun Ken Harthun Profile: Ken Harthun

For those who grew up with the graphical user interface, command line tools are often seen as arcane remnants from the dawn of PC history, a time when badly-dressed nerds sporting horn-rimmed glasses and pocket protectors ruled the universe (well, maybe just the computer lab). For them, nearly all of the command line tools are little known; for us dinosaurs who were typing on terminals well before the PC arrived, there are few of these older tools we haven’t seen. However, as the GUI gradually replaced the command line and we command line geeks began to point and click more and more, some useful tools escaped our notice. One of these is the ten-year-old SDelete by Mark Russinovich of Sysinternals fame. Microsoft acquired Sysinternals in July, 2006 and made all of the excellent tools available free.

Using SDelete

SDelete is a command line utility that takes a number of options. In any given use, it allows you to delete one or more files and/or directories, or to cleanse the free space on a logical disk. SDelete accepts wild card characters as part of the directory or file specifier.

Usage: sdelete [-p passes] [-s] [-q] <file or directory>
sdelete [-p passes] [-z|-c] [drive letter]

-c     Zero free space (good for virtual disk optimization).

-p passes     Specifies number of overwrite passes.

-s     Recurse subdirectories.

-q     Don’t print errors (quiet).

-z     Cleanse free space.

SDelete implements the Department of Defense clearing and sanitizing standard DOD 5220.22-M, which is overkill (see The Great Drive Wiping Controversy Settled at Last), but ensures your data is deleted forever. There is one caveat: SDelete securely deletes file data, but not file names located in free disk space. If you want to be completely sure that all traces of a file are gone, be sure to use the –c or –z option.


Want to see even more useful, little known tools? Check out Sysinternals Live:

Sysinternals Live is a service that enables you to execute Sysinternals tools directly from the Web without hunting for and manually downloading them. Simply enter a tool’s Sysinternals Live path into Windows Explorer or a command prompt as<toolname> or  \\\tools\<toolname>.

You can view the entire Sysinternals Live tools directory in a browser at

February 25, 2009  1:52 AM

Beware the Phone Phishing Scam

Ken Harthun Ken Harthun Profile: Ken Harthun

In my area, there has been a rash of phishing calls targeting bank customers. Coincidentally, today’s WXP News (Vol. 8, #59 – Feb 24, 2009 – Issue #367) addresses the same issue:

You might never click a link in an email purporting to be from your bank, but what if someone from the bank called you on the phone and informed you that your account may have been compromised, and asked for your credentials? The best of these scammers will express concern for “security” and insist that you call them back to “verify” that the call is legitimate. And of course, the number that they give you to call is answered with the bank’s name. Some even go so far as to spoof the caller ID information so your phone displays the name of the bank when they call.

The countermeasure to this is to hang up, dial the bank’s main, published phone number and ask to speak to someone in their security department (some banks call it their “Bank Protection” section). Tell them you believe you may be the target of fraudulent activity. Most banks adhere to some variation of this policy: [XYZ Bank] does not contact customers via email, phone or mail to request or verify security information about passwords, personal identification numbers (PINs), credit card numbers or Social Security numbers.

Check your bank’s website for more information and current security alerts. And don’t give out any information over the phone unless you are absolutely sure who is on the other end.

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