In a circular, NSE said its "market data is being disseminated, supplied and processed by some illegal and unauthorised users".
"Such illegal and unauthorised data is also observed to be used in development of different charting and technical tools," it added.
The caution comes on observations made by DotEx International, a subsidiary of NSE. DotEx International is dedicated to cater the market participants need for data and info-vending products.
In order to promote the use of authorised data and software and to prevent illegal distribution of the data, NSE has advised its members to use only the authorised sources of data and technical software.
The trading members may check with the exchange or DotEx for validating if they are dealing with authorised data vendors, it added.