  In today's world of computers, any kind of information can be made available
within few clicks for different endeavors. The information may be tampered by
changing the statistical properties and can be further used for criminal
activities. These days, Cyber crimes are happening at a very large scale, and
possess big threats to the security of an individual, firm, industry and even
to developed countries. To combat such crimes, law enforcement agencies and
investment institutions are incorporating supportive examination policies,
procedures and protocols to address the complete investigation process. The
paper entails a detailed review of several cyber crimes followed by various
digital forensics processes involved in the cyber crime investigation. Further
various digital forensics tools with detail explanation are discussed with
their advantages, disadvantages, challenges, and drawbacks. A comparison among
all the selected tools is also presented. Finally the paper recommends the need
of training programs for the first res ponder and judgement of signature based
image authentication.
