The accused mastermind behind the Panda Burning Incense worm has not done a very good job of making amends, according to security vendor Symantec.
Li Jun, a 25 year-old man from Wuhan, in central China, was arrested last month for allegedly selling copies of Panda. He is the first man to be arrested in China for virus-writing, according to China's Xinhua state news agency.
In an effort to make an example of Li, state police said they made Li write software that would remove the worm, but after analysing the software, Symantec says this program fails to undo many of the file and registry changes made by Panda. Worse, it is completely ineffective against some variants of the malware.
"This removal tool is not effective against most of the samples we have tested against and isn't fully effective against any of them," wrote Symantec researcher Hon Lau, in a blog posting. "For Li, perhaps he may have learned the hard way that... it is much easier to write a program to cause destruction than it is to repair the damage."
Panda, which is also known as Fujacks and Radoppan.T was written in October 2006 and has since spread widely within China. According to Xinhua, Li made 100,000 renminbi (£850) by selling copies of the worm to criminals who then distributed it. Li was one of eight men arrested in connection with the affair.
Li's uninstaller tool comes with an apology from the worm-writer himself, claiming that the program was written for research purposes, Symantec's Hon said. "He ends with a warning to beware of future threats (from others), and to take the necessary precautions," he wrote.