Blizzard watermarking WoW screenshots

Anyone still playing Blizzards highly successful MMORPG World of Warcraft? Then you are probably used to Blizzard's Warden client running all the time in the background and do not mind it. A forum user over at the Owned Core found out that Blizzard appears to have added a another way to track WOW users in the game. According to the information, screenshots taken with World of Warcraft's internal screenshot tool are watermarked automatically.

The watermarks contain account and realm information, including the IP address of the realm the screenshot was taken on, the characters' account ID and name, and the time the screenshot was taken.

Instructions have been posted that outline how you can reveal the watermark:

• Go to a location with little textures, e.g. Dalaran in Crystalsong Forest
• Type /console SET screenshotQuality "9" to set the quality of the screenshot to 9 (the default is 3). All quality levels but 10, the highest, have the watermark included.
• Use Alt-z to zoom in until you see a a clear, white area with no textures
• Open the image in an image editing program and use a Sharpening filter on it several times.
• The WoW watermark should now be visible

Some readers of the guide first suggested that the patterns could be random artifacts, but that was refuted quickly as random artifacts do not produce account IDs. The thread contains links to tools that anyone can use to reveal the account ID and other information stored in the watermark.

Third parties may also be able to use the information to their advantage, for instance by trying to brute force their way in using known account names and common passwords.

Two questions arise:

1. Why is Blizzard watermarking World of Warcraft screenshots?
2. What can you do to block the watermarking?

Why is Blizzard watermarking World of Warcraft screenshots?

The most likely explanation is to connect events shown on screenshots to a server and account. If someone posts a hack or a glitch, Blizzard can use the information that the watermark provides to locate the server and user to analyze and penalize. The method can also be used to locate private servers, and users who are under NDA if they post screenshots.

What can you do to block the watermarking?

You can change the screenshot quality level to 10 with the console command /console SET screenshotQuality "10".

Another option is to not use WoW's internal screenshot tool but an external program to create the screenshots.