---
tags: NASA
---
# NASA 2017 Midterm Practice


## 1.

---

## 2.

### 1.

Filter: `dns && ip.addr == 140.112.28.0/19`

### 2.

Filter: `dhcp`

`e0:ac:cb:69:44:90`
`78:f8:82:b1:74:70`
`48:4b:aa:00:1c:56`
`d4:f4:6f:98:09:54`

### 3.

Filter: `http contains "Mac"`

`54.243.198.221`
`206.108.53.86`
`163.28.5.35`
`163.28.5.40`

---

## 3.

---

## 4.
Use Conversations->TCP->Follow Stream
* Find Meow’s private key in thepcapfile

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: AES-128-CBC,55CE2F9FC2E46A7465CDF0B134A2E008

U+nsjO/8swdsg/JjlEYYQapAa/eqgMmgmrwuvgrb9vDFEMzVkNZ7xlaVYyw67E3z
EJOo0nsQUsqP2y4c4hJYPtBR2RYpejVCV8uwsmY1vyV099fXN+IKsyllwNF39Ls3
eDWoE50DRkNvXuzXWVcstaQG924U3oYCkiqUXRpMSfYd8784TOSylX+J1976/ip9
~~~省略~~~
SOsSazr0MXLqb4tyHvUWij9QPfs1WhYOUBf/qBjOh3Lu/Jg/Syvt0KvfwaeuVt6s
eYuPRsEZ2FC9GoWy2nlZLhi0bYcHymsX1oZRIjky3LRNLhIGYk/aBnjwgjTa8sQy
zh+Ox80BmpgB/DwophmZeAjYVXC0wQgrP+At82Oxf13mlLD6ujDYz2K7OjNs5c4y
-----END RSA PRIVATE KEY-----

* Find the private key’s passphrase in thepcapfile
`my_password_dont_meow_this`
* Find ssh server’s listening port in thepcapfile
* Find the hostname/IP of the remote server in thepcapfile

---

## 5.

#!/bin/bash
ans='195a30a1d1561cbc0ae7c488b93d037f6b713354'
og='Base{32,64}_Is_Stupid_But_Sometimes_Useful'

D2B=({0..1}{0..1}{0..1}{0..1}{0..1})
enc=('base32' 'base64')

for((i=0; i<32; i++)); do
try="$og"
bini="${D2B[$i]}"
for ((j=0; j<5; j++)); do
bit="${bini:${j}:1}"
try=`echo "$try" | ${enc[${bit}]}`
done
try=`echo "$try" | sha1sum`
try="${try:0:40}"
if [[ "$try" == "$ans" ]]; then
echo "${enc[${bini:0:1}]} -> ${enc[${bini:1:1}]} -> ${enc[${bini:2:1}]} -> ${enc[${bini:3:1}]} -> ${enc[${bini:4:1}]}"
break
fi
done

---

## 6.

#!/bin/bash
filename="country.csv"
echo "here"
IFS=''; while read -r line; do
code=`echo $line | cut -d ',' -f 1 | tr '[:upper:]' '[:lower:]'`
full=`echo $line | cut -d ',' -f 2`
if [[ $code == "id" ]]; then
continue
fi
dns_record=`dig +short ftp.${code}.debian.org`
echo "$full ftp.${code}.debian.org"
if [[ -n "$dns_record" ]]; then
index=0
record_lines=()
IFS=''; while read -r dline && test -n "$dline"; do
record_lines["$index"]="$dline"
index=$(($index+1))
done <<< "$dns_record"

index=0
unfinished='false'
while [[ $index -lt ${#record_lines[@]} ]]; do
rline="${record_lines[$index]}"
# echo "$rline"
if [[ "${rline:0:1}" =~ [0-9] ]]; then
IP="$rline"
provider=`curl ipinfo.io/$IP 2> /dev/null | grep '"org":' | cut -d ':' -f 2 | sed 's/\"//g' | sed 's/,$//g'`
echo "$IP, provided by$provider"
unfinished='false'
else
echo -n "$rline => "
unfinished='true'
fi
index=$(($index+1))
done
if [[ "$unfinished" == 'true' ]]; then
echo "unresolvable"
fi
# break
else
echo "unresolvable"
fi
echo ""

done < "$filename"
unset IFS

---

## 7.

#!/bin/sh
n=6
min=8
max=10
re='^[0-9]+$'
while [[ $# -gt 0 ]]
do
key="$1"
case $key in
-n)
n="$2"
if ! [[ $2 =~ $re ]]; then
echo "ERROR" >&2
exit 1
fi
shift
shift
;;
-m)
min="$2"
if ! [[ $2 =~ $re ]]; then
echo "ERROR" >&2
exit 1
fi
shift # past argument
shift # past value
;;
-x)
max="$2"
if ! [[ $2 =~ $re ]]; then
echo "ERROR" >&2
exit 1
fi
shift # past argument
shift # past value
;;
*)
echo "ERROR" >&2;
exit 1
;;
esac
done

for ((i = 0 ; i < $n ; i++ )) do
len=`shuf -i $min-$max -n 1`
rand=`cat /dev/random | tr -dc 'a-zA-Z0-9' | fold -w $len | head -n 1`
echo "$rand"
done

## 8.

#!/bin/sh
cat fail2ban.log | grep fail2ban.actions | grep NOTICE | grep Ban > banned.tmp
gawk -i inplace '{print $(NF)}' banned.tmp
wc -l banned.tmp
cat banned.tmp | uniq > ip.tmp
wc -l ip.tmp
touch country.tmp
cnt=0
while read ip; do
echo "$cnt"
((cnt=cnt+1))
whois $ip | awk ' /[Cc]ountry/{print $2;exit}' >> country.tmp
done < ip.tmp
cat country.tmp|sort|uniq -c|sort

## 10.

vi /etc/sysconfig/network-scripts/ifcfg-<interfaces>
onboot=yes