Can there be a Trojan in the antivirus?

Question

Antivirus

Downloaded Dr. Web Cureit so he found a trojan in the Avira antivirus folder.
Could this be?

Name: trojan.downloader41.13367
Path: C:\Program Files (x86)\Avira\somewhere here

Answer 1

Of course, I am not special in the design of anti-virus software, but something can be understood purely from general considerations.
First, antiviruses are weapons, so a certain amount of secrecy is considered acceptable about their inner workings. The authors of anti-virus algorithms try not to reveal their device, for obvious reasons.
Secondly, among these algorithms, it is quite possible to have virus-like ones (the so-called "virus-like behavior"). This is one of the main reasons why it is not recommended to install several different antivirus programs on the computer, since there is a possibility that they will start to fight with each other.
What happened to you.
But this does not mean at all that your antivirus program is infected. Because, thirdly, the authors of anti-virus software use all possible measures to protect their works from unwanted modifications. Recall, for example, how difficult it can be to completely remove some antivirus programs - often this is not possible without special utilities that the authors of the antivirus programs themselves provide, being aware of this problem.
Nevertheless, I would be careful not to trust antiviruses 100%. It would be best to organize a cross-check of suspicious content with other antiviruses, launching them from third-party media.

Answer 2

The situation is ridiculous. Check it on virustotal.
:)