Title

AIX must use Loadable Password Algorithm (LPA) password hashing algorithm. (Cat I impact)

Discussion

The default legacy password hashing algorithm, crypt(), uses only the first 8 characters from the password string, meaning the user's password is truncated to eight characters. If the password is shorter than 8 characters, it is padded with zero bits on the right. The crypt() is a modified DES algorithm that is vulnerable to brute force password guessing attacks and also to cracking the DES-hashing algorithm by using techniques such as pre-computation. With the Loadable Password Algorithm (LPA) framework release, AIX implemented a set of LPAs using MD5, SHA2, and Blowfish algorithms. These IBM proprietary password algorithms support a password longer than 8 characters and Unicode characters in passwords.

Check Content

From the command prompt, run the following command to check system wide password algorithm: # lssec -f /etc/security/login.cfg -s usw -a pwd_algorithm usw pwd_algorithm=ssha512 If the "pwd_algorithm" is not set to "ssha512", or "ssha256", this is a finding.

Fix Text

From the command prompt, run the following command to set system wide password algorithm to "ssha512" so that it supports passwords longer than 8-character: # chsec -f /etc/security/login.cfg -s usw -a pwd_algorithm=ssha512 For each users who have hashed passwords in "/etc/security/passwd" file that does not start with "{ssha512}", run passwd commands to reset the users' passwords so that they have to change their passwords in the next login: # passwd [user_name]

Additional Identifiers

Rule ID: SV-215225r508663_rule

Vulnerability ID: V-215225

Group Title: SRG-OS-000078-GPOS-00046

Expert Comments

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