IBM AIX 7.2, and 7.3 and IBM VIOS 3.1, and 4.1 stores NIM private keys used in NIM environments in an insecure way which is susceptible to unauthorized access by an attacker using man in the middle techniques.
IBM strongly recommends addressing the vulnerability by following the instructions in the fixes and remediation section of the IBM security bulletin: https://www.ibm.com/support/pages/node/7251173