us cyber security chief resigns man making sure us computer networks safe secure resigned year post amit yoran director national cyber security division within us department mother country certificate created postdate attacks division tasked improving us defences malicious hackers viruses threats reports suggest left division given enough clout inside larger organisation mr yoran took post september first labor get cyber security sectionalization running organisation staff people budget division charged call up carrying carry out make us networks imperviable attack disruption viruses worms hack attacks become commonplace end months mr yoran oversaw creation cyber alert system sends warnings big strike viruses meshwork attacks occur warnings also contained information firms organisations could protect attacks cyber surety division also audited us government mesh discover exactly sitting electronic network next whole step founding scanning organization identify vulnerabilities made federal networks machines susceptible attempt malicious hackers virus writers mr yoran division also work identify networks machines broken cyber criminals despite success mr yoran left mail service short close last week reportedly giving one day bill bosses department homeland security amit yoran valuable contributor cyber security issues past year appreciate efforts starting section cybersecurity computer programme said department homeland security spokeswoman reports suggested mr yoran felt frustrated lack prominence given mold protect threats wider homeland organisation attempt us politicians pass practice of law promote mr yoran raise profile department work mired congress