the second column is the certificate expiration date in ASN1_TIME format. The entry '180301135738Z' means the certificate enddate is
2018, March 01 13:57:38 GMT
someone else asked the same question on the openvpn-users mailing list; I've written a little script which attempts to recreate the index.txt file. Works for several index.txt files that I could find. YMMV.
#!/bin/bash
if [ $# -eq 0 ]
then
echo "Usage: $0 *.pem"
exit 1
fi
for cert
do
enddate=`openssl x509 -enddate -noout -in $cert | sed 's/notAfter=//' | awk '\
{ year=$4-2000;
months="JanFebMarAprMayJunJulAugSepOctNovDec" ;
month=1+index(months, $1)/3 ;
day=$2;
hour=substr($3,1,2) ;
minutes=substr($3,4,2);
seconds=substr($3,7,2);
printf "%02d%02d%02d%02d%02d%02dZ", year, month, day, hour, minutes, seconds}'`
serial=`openssl x509 -serial -noout -in $cert |sed 's/serial=//'`
subject=`openssl x509 -subject -noout -in $cert |sed 's/subject= //'`
echo "V $enddate $serial unknown $subject"
done
