Companies that fail to implement an effective cross-selling program actually do a disservice to their customers and in effect, leave the backdoor open to their competitors.

不能实施有效的交叉销售项目的公司实际上危害了他们的顾客，并且对他们的竞争者打开了的后门。

youdao

Once launched, the virus is designed to install a Trojan horse or backdoor program, and allow investigators to record everything typed into that machine, thereby getting around encryption and passwords.

CNN: Top Technology Stories for 2001

The backdoor could take the form of an installed program or subvert the system through what is known as a rootkit, a malicious software hard to detect.

FORBES: Worm Attacks Coming For Google's Android - Kaspersky Lab