It doesn't. All that it shows seems to be some false positives from heuristic analysis of mostly bottom of the barrel antiviruses. Not actual virus signature detection.
Malwarebytes detects malware, too.
https://www.stcmicro.com/rar/
STC actually have a copy of the Keil C51 compiler in their downloads section, with the crack tool included.
So professional.
It looks like the Keil_lic_v2.exe crack is the file that triggers the
Malware.Heuristic. So it's just triggered because it modifies unrelated system files or something?
I guess this isn't the .rar file I actually need, though, if I already have a legit copy of Keil C51.
This page describes the process of adding it to Keil, which is actually done with the stc-ispX.XX.zip files. (Those get flagged as malware, too, but by fewer engines...)
Edit: Malwarebytes and Avast didn't have a problem with stc-isp-15xx-v6.88I-tiny.zip, so I ran it, but then Avast had a problem with it. "Anti-Exploit shield".
Oh, it may just be from the software trying to contact
www.stcmcudata.com which is on URL:Blacklist.
But that file doesn't seem to include the Keil modifications. The other one does? But that one asks for administrator permissions,
also gets flagged as malware by a few engines, and includes instructions for modifying your system to allow drivers without signatures.
"由于 Windows10 64 位操作系统在默认状态下,对于没有数字签名的驱动程序是不能安装成
功的。所以在安装 STC-USB 驱动前,需要按照如下步骤,暂时跳过数字签名,即可顺利安
装成功。"
"Since Windows 10 64-bit operating systems by default cannot be installed as a driver without a digital signature for
Therefore, before installing the STC-USB driver, you need to follow the steps below to skip the digital signature for the time being, so that you can install it without any problems."
'电脑重启后,会弹出“启动设置”界面,按“F7”按钮来选择“禁止驱动程序强制签名”项'
'After the computer reboots, the "Startup Settings" screen will pop up, press the "F7" button to select the "Disable driver forced signature" item'
I've never seen any other embedded development software that requires all this...