Five security leaks that need plugging

John Brandon identifies gaps organisations must fill

1. Unauthorised smartphones on wi-fi networks

Smartphones create some of the greatest risks for enterprise security, mostly because they're so common and because some employees just can't resist using personal devices in the office -- even if their employers have well-established policies prohibiting their use.

"The danger is that cell phones are tri-homed devices -- Bluetooth, wi-fi and GSM wireless," says Robert Hansen, of internet security consulting firm SecTheory. Employees who use their personal smartphones at work "introduce a conduit that is vulnerable to potential attack points," he says.

If you use a device like a smartphone that spans multiple wireless spectrums, "someone in a parking lot could use a Bluetooth sniper rifle that can read Bluetooth from a mile away, connect to a smartphone, then connect to a corporate wireless network," says Hansen, who is also known by his alias, RSnake. Bluetooth is the open portal that lets a hacker access wi-fi and therefore the corporate network.

Hansen says policies that simply disallow smartphones aren't likely to be effective -- employees will be too tempted to use their gadgets at work even if they're prohibited. Instead, he says IT should allow only approved devices to access the network. And that access should be based on MAC addresses, which are unique codes that are tied to specific devices -- making them more traceable.

2. Open ports on a network printer

The office printer is another seemingly innocuous device that represents a security risk, although most companies are oblivious to the danger. Printers have become wi-fi-enabled over the past few years, and some even use 3G access and telephone lines for faxes. Some models do block access to certain ports on printers but, as Hansen says, if there are 200 blocked ports for printers at a large company, there might be another 1,000 ports that are wide open. Hackers can break into corporate networks through these ports. A more nefarious trick is to capture all printouts as a way to steal sensitive business information.

"One of the reasons you do not hear about it is because there is no effective way to shut them down," says Jay Valentine, a security expert. "We see access all the time via network ports in the electric utility industry, which is a major accident waiting to happen."

The best way to deal with this problem is to disable the wireless options on printers altogether. If that's not feasible, IT should make sure all ports are blocked for any unauthorised access, says Hansen. It's also important to use security management tools that monitor and report on open printer ports.

3. Custom-developed web applications with bad code

Just about every enterprise security professional lives in fear of holes created by sloppy programming. This can occur with custom-developed software as well as with commercial and open-source software. Hansen says one common trick is to tap into the xp_cmdshell routine on a server, which an inexperienced programmer or systems administrator might leave wide open for attack. Hackers who do that can gain full access to a database, which provides an entryway to data and a quick back door to networks.

Hansen says PHP routines on a web server can also be ripe for attack. Small coding errors, such as improper safeguards when calling a remote file from an application, provide a way for hackers to add their own embedded code. This can occur if a developer wasn't careful to restrict which files might be called based on a user's form input, or a company blog using a trackback feature to report on links back to its posts, without first sanitising stored URLs to prevent unauthorised database queries.

The most obvious fix to this problem is to avoid some software such as freely available PHP scripts, blog add-ons and other code that might be suspect. If such software is needed, security-monitoring tools can detect vulnerabilities even in small PHP scripts.

4. Social network trickery

Facebook and Twitter users can be fooled into divulging sensitive information. Usually, these types of attacks are subtle and not necessarily traceable.

"People looking for jobs are often willing to divulge [personal] information," says Hansen, who says one of his clients told him about how a hacker used a fake email address from a job-search website to pose as a recruiter. He declined to elaborate on this example to protect the client, but it's an example of what he calls the "confused deputy" scenario, where someone claiming to be, say, a recruiter for contacts an employee, and the employee believes that the caller is, in fact, a recruiter and doesn't ask to verify his credentials. Hansen says it's the same as getting an envelope in the mail -- just because the envelope has a certain return address, it doesn't mean that the contents actually came from that sender.

Companies should use email verification systems that confirm the identity of a sender. These verifications send an email back to the address to confirm the sender's credentials.

5. Employees downloading illegal movies and music

P2P networks just won't go away. In a large company, it's not uncommon to find employees using peer-to-peer systems to download illegal wares or setting up their own servers to distribute software.

"P2P networking should, as per policy, be completely blocked in every enterprise," says Winn Schwartau, CEO of The Security Awareness Company, a security training firm. "The P2P ports should be completely shut down at all perimeters and ideally at the company's endpoints. P2P programs can be stopped through white/black listings and filters on the enterprise servers."

"Injecting hostile code into P2P files is [not difficult] and can create a beachhead within an organisation, depending upon the code design," he says. He suggests a technique called "resource isolation", which essentially controls which applications users are allowed to access based on permission rights. Different operating systems do that in slightly different ways, Schwartau says, but it's worth pursuing in situations where a corporate policy is lacking or isn't followed.

Schwartau encourages IT shops to conduct regular sweeps of all company networks and servers to look for P2P activity and to be vigilant about blocking any P2P activity.

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