The number of free Android apps that may be infected with malware this week has increased to more than 50. While some of these apps would look suspicious, others named things like "Quick Notes" or "Chess" seem innocent enough, and you might not think twice about downloading them.

Here are five quick tips to help keep your Android phone malware free:

  1. Always research the publisher of the app. What other apps are they offering? Do any of them look a bit shady? If so, you should probably stay away.
  2. Read online reviews. Android Market reviews may not always be truthful. Check around to see what reputable websites are saying about the app before you hit that download button.
  3. Always check app permissions. Whenever you download or update an app, you are given a list of permissions for that app. That alarm clock app you are looking at probably shouldn't need to be looking through your contacts. The general rule of thumb is if an app is asking for more than it does, you should probably skip it.
  4. Avoid directly installing Android Package files (APKs). When Angry Birds first came to Android, you could only get it through a third party. This is called "sideloading" or, installing apps using an .APK file. While Angry Birds wasn't malware, it is highly advisable not to download and install .APK files that you randomly come across. Most of the time you won't know what the file contains until you install it. By then it's too late.
  5. Get a malware and antivirus scanner on your phone. While many still think that antivirus scanners on phones are useless, maybe outbreaks like these will change minds. Several different big name security companies already offer mobile security options, many of them free. I myself had downloaded "Spider Man," which is on a bad list. My Lookout software identified it as a Trojan.

Infected apps list published by Android user "Myournet"

  • Advanced Currency Converter
  • App Uninstaller
  • Chess
  • Dice Roller
  • Falling Ball Dodge
  • Falling Down
  • Funny Paint
  • Hilton Sex Sound
  • Hot Sexy Videos
  • Photo Editor
  • Scientific Calculator
  • Screaming Sexy Japanese Girls
  • Spider Man
  • Super Guitar Solo
  • Super History Eraser
  • Super Ringtone Maker
  • Super Sex Positions

Infected apps list published by Android User "Kingmall2010"

  • Advanced App to SD
  • Advanced Barcode Scanner
  • Advanced Compass Leveler
  • Advanced File Manager
  • Best password safe
  • Bowling Time
  • Magic Strobe Light
  • Music Box
  • Sexy Girls: Japanese
  • Sexy Legs
  • Super Stopwatch & Timer
  • Supre Bluetooth Transfer
  • Task Killer Pro

Infected apps list compiled under the developer name "we20090202":

  • Advanced Sound Manager
  • Basketball Shot Now
  • Bubble Shoot
  • Color Blindness Test
  • Finger Race
  • Funny Face
  • Magic Hypnotic Spiral
  • Omok Five in a Row
  • Piano
  • Quick Delete Contacts
  • Quick Notes
  • Super Sexy Ringtones
  • Tie a Tie

Also on the lists are the foreign language apps shown at left.

Lookout Mobile Security, which provides security software for mobile phones, posted a list of 56 Android applications on its blog that have been infected with DroidDream, a new type of Android malware that roots your phone and gains access to as much personal information as it can. The apps also can open a back door, allowing more executable code to be downloaded to your phone without you being aware of it.

A few of these apps have already been downloaded by at least 50,000 users, making this one of the most widespread cases of Android malware to date. While the apps have been pulled from the Android Market, Google is investigating them and has not yet moved to wipe them remotely from people's phones.

Lookout has issued an update to its mobile security software. It also advises that if you have downloaded any of these apps, to run its malware scanner and to email the Lookout support center. Mashable (who earlier today posted a list of infected apps compiled by Myournet) suggested returning your phone to your carrier as your data and security may be compromised.

With more and more malware emerging for the platform every day, Android users would do well to be more careful and pay more attention to what happens on their phones. You have to remember that smartphones are essentially computers, and all computers are vulnerable to attack by malicious software.