Tag Archives: security

Linux, Security, Zabbix

Zabbix SELinux policy generation

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Commands to query the auditlog for Zabbix relevant queries and create/import a compiled policy file within Zabbix

Could be adapted to generate policies for any other system.

The suggestion is to set SELinux to permissive (setenforce=0) execute the action and afterwards create the policy based on the logged events. If the policy does not work on the first try after re-enabeling SELinux again it it could happen that a call was blocked (which is also logged within the auditlog) that was not blocked with SELinux in permissive mode. Therefore it could help creating a new human readable policy (.te-file) and checking the first version vs. the second version + merging them. 

filename=zabbix-server
cat /var/log/audit/audit.log  | grep zabbix | audit2allow -m $filename >> $filename.te
checkmodule -M -m -o $filename.mod $filename.te
semodule_package -o $filename.pp -m $filename.mod
semodule -i $filename.pp
 
 
#restorecon -R -v /run/zabbix/zabbix_server_alerter.sock    #suggested by the policygenerator
Linux, Security, Tools

Get CVE information from NIST NVD and RHEL

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Just two littel scripts that come handy if you want to download all the CVE info in JSON format for offline use.

#!/bin/bash
urls=$(curl https://nvd.nist.gov/vuln/data-feeds#JSON_FEED | grep 'https://' | grep -i json.gz | sed 's/.*href=//g' | cut -d\'  -f2)

mkdir -p ./nistNvdJson
cd nistNvdJson
for l in $urls;
do
wget $l
done
gunzip *
Donwload NIST NVD CVEs in JSON

 

#!/bin/bash


loopVar=1
dataDir="rhelCveData"
mkdir $dataDir -p
echo "getting data:"
T="$(date +%s)"
while [[ $loopVar -ne 0 ]];
do
        echo -n "-$loopVar- "
        data=$(curl -s https://access.redhat.com/labs/securitydataapi/cve.json?page=$loopVar)
        if [[ "$data" == "[]" ]]; then
                loopVar=0
        else
                toFile=$toFile${data:1:-1}", "
                let loopVar=loopVar+1
        fi
done
T="$(($(date +%s)-T))"
echo "[${toFile::-2}]" >> "$dataDir/rhelCve.json"
sed -i 's/^\[\]$//g' "$dataDir/rhelCve.json"
printf "Got data in: %02dd:%02dh:%02dm:%02ds\n" "$((T/86400))" "$((T/3600%24))" "$((T/60%60))" "$((T%60))"
Get CVE infos for RHEL

 

Additional information:
If you query the NIST NVD Data and search for RHEL CPEs you won’t get a lot of hits as only a smal percentage of the CVEs that affect Red Hat software has the correct CPE attached. However – NIST NVD is nice to have because in the Red Hat CVEs only the total CVSS score is listed but no detailed vulnerability metrics are included.

Linux

Remove Oracle ApEx from the database

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Because Nessus seems to dislike Oracle ApEx we needed to remove it from the database.  Oracles manual regrading the removal is pretty straight forward (https://docs.oracle.com/database/121/HTMIG/trouble.htm#HTMIG270), but I wanted to do it in a single none intreactive line which makes it easier to do de removal automated.

so – here it is:

echo quit | sqlplus -S "sys/sys as sysdba" @$ORACLE_HOME/apex/apxremov.sql