Using email messages has been the most straight forward proposition for cybercrimes. Digital images, movie files, pictures are typical media contents which can be attached to email messages. The child pornography distributors use email messages to impart child pornographic content. Sharing pictures in this method gives opportunity to the offender to send an image with a context without describing the content of the message.it means that the content of the message must be something else but the attachments of the emails are susceptive.
Although several laws have been implemented to curb such kind of menace, but all this type of crimes still do occur. Whenever a cybercrime of such nature are reported, law enforcement agencies usually fails to come up across appropriate legal evidence to present in the court of law. Child pornography issues bring up situations where prosecution might have to prove that the accusing has been using emails to send messages related to pornographic contents of a child.
Traditional techniques and methods simply are not viable to cater for the extraction of culpable evidence that investigators have to analyze. With the digital evidence available in multiple image formats, the problem for forensic experts is getting more difficult to tackle.
However recent trends in investigation procedure have given rise to techniques which can help examiners to potentially examine evidence. Forensic investigators may employ techniques like skin tone analysis which is done as part of the verification of the email database items to search for pornographic content present as a part of email messages.
What exactly is Skin Tone Analysis?
It can be described as a technology basically carried out for image analysis on the basis of pixels present in an image. The main purpose behind the technique is to identify images which are of suspicion based on skin tone values. The skin tone detection filter that can recognize pictures which has a large skin color count from the aggregate image results.
Forensic investigators can avail image detection technology with a product known as MailXaminer. Let’s see how it works out in assisting examiners to scoop out evidence related to images.
Working of MailXaminer
Users can download the product from the website of MailXaminer. After successfully downloading and installing it, users can find out an extremely intuitive interface. You can select the option “Open case” to start with a new case. Enter the details that appears on the window and save it.
The next settings which are carried out by the forensic examiner is given as follows
Options >> Settings >> Advance settings
On selecting the above settings, a new window will open. Here, choose the tab” Image Analysis” and set the “Switch Image Analysis” to on mode. Besides, that users can also adjust the sensitivity level of the image analysis engine. If you set the range as high then the detection rate of the images will be high. Then click on the “Save” button.
The next step consists of scanning the email database which is of suspicion. For this, select the option “Scan File” which is present on the top of the menu bar. Then a pop-window will appear. Select your email account type. If it is a web=based email account then select the option “web”. Here, you can select the email provider and then provide the credential for that particular email account.
Once you have entered the credential concerned to that specific email account, the software will download the entire email database. Users can also monitor the progress of downloading. If they want to stop the process in the middle then can select the“stop” option to put the process to stop.
After the emails are successfully downloaded by the application. Select “view” button located at the bottom of the screen. On selecting the view tab, you will be immediately re-directed to a new window given below
Here, you will get the details of all the folders that are present in the implicated email database. Now click on the option “Media” present on the lower left hand of the screen.
After selecting the “Media” option, users will get details of all the media files present within the email messages. The MailXaminer application will provide a list of all types of media files which are present in various type of file formats.
One can notice that there is a category of files listed as “suspected attachments”. This refers to the list of image attachments which are considered to be dubious. Further, on extending this option, three categories are labelled: Moderate, High, and Low. All these three categories refer to the intensity of suspected images present within the email messages.
Further on selecting a particular category say “Low”, all the images which have low suspicion will be listed. You can also select to view a particular image by the different view modes provided by the utility. Suppose a user wants to view the images in “Normal Attachment view” then the images will appear in the following format.
The technique which works over here in this example is that the image search engine after filtering process found all the images associated with the entire email database having low skin color count. So, it has listed the images as considerably of less suspicion i.e. “Low” category.
With complete email header analysis by MailXaminer forensics utility; forensic investigators can bring out necessary evidence so as to prove the defendant accused of passing on child pornographic images to be guilty of crime in the judicial court. Besides, providing the mechanism of skin tone analysis, the MailXaminer has other beneficial features like analyzing email header of various email file formats, Gmail, Office 365 emails and other email platforms without the requirement of installing the supported email client.