Human Resource Development Minister Kapil Sibal on Tuesday hit out at the IIMs for the botched Common Admission Test (CAT) and said they should have been more careful in preparing for the exam.

The HRD minister said the IIMs must make a detailed inquiry into the server crash which affected at least 8000 students.

After three days of chaos marred the CAT online exams, the Union HRD Minister lashed out at the IIMs for the botched test.

The trouble has now been traced to two viruses - the 'Conflicer' and 'W32 Nimda'. The two viruses attacked the system causing it to slow it down.

Efforts are now on to quarantine the systems from these viruses to ensure smooth conduct in the remaining days.

Tests at 47 labs at centers were called off on the first two days and 33 labs on Monday, as students faced problems in logging at the exam centers affecting nearly 8,000 aspirants who will be rescheduled.

These include centers in Delhi (3), Bhopal, Bangalore, Bhubaneswar, Chandigarh, Ghaziabad, Coimbatore, Hyderabad, Calcutta, Lucknow, Mumbai, Nagpur and Varanasi.

Over 2.4 lakh students registered for the CAT this year , which is being conducted through computers for the first time. The IIMs for the first time have entrusted the task of conducting the CAT to Prometric, an American firm, which is organising the computer-based test over a period of 10 days.

Since the incident was reported, the director of Indian Institute of Management, Ahmedabad (IIM-A) is constantly in touch with his counterparts in other IIMs to solve the problems.