Ensure No World-Writable Files Exist
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Description
It is generally a good idea to remove global (other) write access to a file when it is
discovered. However, check with documentation for specific applications before making changes.
Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured
application or user account. Finally, this applies to real files and not virtual files that
are a part of pseudo file systems such as sysfs
or procfs
.
Rationale
Data in world-writable files can be modified by any user on the system. In almost all
circumstances, files can be configured using a combination of user and group permissions to
support whatever legitimate access is needed without the risk caused by world-writable files.
Shell script
The following script can be run on the host to remediate the issue.
#!/bin/bash
FILTER_NODEV=$(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
PARTITIONS=$(findmnt -n -l -k -it $FILTER_NODEV | awk '{ print $1 }')
for PARTITION in $PARTITIONS; do
find "${PARTITION}" -xdev -type f -perm -002 -exec chmod o-w {} \; 2>/dev/null
done
# Ensure /tmp is also fixed whem tmpfs is used.
if grep "^tmpfs /tmp" /proc/mounts; then
find /tmp -xdev -type f -perm -002 -exec chmod o-w {} \; 2>/dev/null
fi
Warning
This rule can take a long time to perform the check and might consume a considerable
amount of resources depending on the number of files present on the system. It is not a
problem in most cases, but especially systems with a large number of files can be affected.
See https://access.redhat.com/articles/6999111
.