Remove protection from files

Employer
[no-member:pro]Viktor[/no-member:pro]
Project parameters
Type of cooperationOne-time project
SectionWeb development
Prepaymentwithout prepayment
Payment methodsBank transfer, Electronic money
Acceptance of requestsfrom Apr 4, 2019 until Apr 11, 2019
Project description
After hacking the site by hackers, some site files were encrypted, and they contain a redirect to another site and malicious in addition. As a matter of urgency, you need to remove protection from these files, remove malicious code and test the site for vulnerabilities so that this situation does not recur in the future. The site is currently closed to users. I will send the site files to everyone personally. There are 6 files encoded. In the answers, be sure to indicate the approximate cost of work and your experience in the field of "treatment" sites.