Information
All groups should have a unique GID on the system.
All groups should have an individual and unique GID. If GID numbers are shared this could lead to undesirable file and directory access.
Solution
- Examine the group IDs (GID) of all locally configured accounts:
cut -d: -f "1 3" /etc/group | sort -u | cut -d: -f 2 | sort -n | uniq -d
If the command has output there is at least one duplicate GID number. Determine any duplicates within the /etc/group file:
cut -d: -f "1 3" /etc/group | sort -u | cut -d: -f 2 | sort -n | uniq -d | while read GID; do
cut -f "1 3 4" -d : /etc/group | /usr/bin/sort -t: -k2n | grep ":${GID}:"
done
- Examine the names of all locally configured groups:
cut -d: -f "1 3" /etc/group | sort -u | cut -d: -f 1 | sort | uniq -d
If the command has output there is at least one duplicate group name. Determine any duplicates within the /etc/group file:
cut -d: -f "1 3" /etc/group | sort -u | cut -d: -f 1 | sort | uniq -d | while read groupname; do
cut -f "1 3 4" -d : /etc/group | /usr/bin/sort -t: -k2n | grep "${groupname}:"
done
NOTE : Any duplicates returned should either be deleted or have the GID changed. Be careful. We recommend you examine any accounts assigned to a duplicate and ensure the account is neither losing nor gaining authorized group access through any remedial action.
To remove:
rmgroup <groupname>
To change the GID:
chgroup id=<id> <groupname>