Major Samsung Galaxy S3 bug costs users in unnecessary mobile data use

Researchers at the University of Massachusetts Amherst have discovered a bug in the Samsung Galaxy S3 mobile web browser that causes users to use significantly more mobile data to download an image than necessary.

The discovery was made by Emmanuel Cecchet, Robert Sims, Xin He, Prashant Shenoy in a research paper to be presented to the IEEE/ACM International Symposium on Quality of Service.

The researchers were first alerted to the bug by a lag on downloading image heavy websites on the Galaxy S3, compared to other Android smartphones.

“When comparing our results on the different devices and networks for our Wikipedia trace, we noticed significantly higher latencies for our Samsung S3 smartphone on both WiFi and 3G,” the researchers wrote.

The researchers discovered that on websites where a website makes same image available at a range of different resolutions, the Galaxy S3 would attempt to download all the images instead of just choosing one.

“By looking at the recorded HTML page source, we saw that Wikipedia pages use Srcset HTML tags that indicate a list of images to pick from depending on the resolution and magnification needed by the device,” the researchers explain.

“It turns out that the S3 browser has a bug and systematically downloads all images in a Srcset instead of picking only the one it needs. This can result in a massive amount of extra data download.”

The researchers discovered the bug can cause users to download triple the amount of data they need on some webpages.

“The Wikipedia page dedicated to the [Microsoft] Internet Explorer [web] browser that typically requires 600KB of data download jumped to 2.1MB on the S3. This bug significantly affects the Wikipedia performance on 3G where these massive number of requests for image downloads overwhelmed the network and ended up timing out rendering an incomplete page.