PuTTY is one of the oldest and most popular SSH clients originally for Windows but now available on several platforms. It has won corporate support and endorsement and is prepared and bundled within several third-party repositories.
Unfortunately the 0.74 stable PuTTY release does not safely guard plain-text passwords provided to it via the -pw command line option for the psftp pscp and plink utilities as the documentation clearly warns. There is evidence within the source code that the authors are aware of the problem but the exposure is confirmed on Microsoft Windows Oracle Linux and the package prepared by the OpenBSD project.
After discussions with the original author of PuTTY Simon Tatham developed a new -pwfile option which will read an SSH password from a file removing it from the command line. This feature can be backported into the current 0.76 stable release. Full instructions for applying the backport and a .netrc wrapper for psftp are presented also implemented in Windows under Busybox.