IV$.$ There is an active connection between a Telnet client $(10\mathrm{.}0\mathrm{.}2\mathrm{.}5)$ and a Telnet server

$(10\mathrm{.}0\mathrm{.}2\mathrm{.}9).$ The server has just acknowledged a sequence number $1000,$ and the client has

just acknowledged a sequence number $3000.$ An attacker wants to launch the TCP session

hijacking attack on the connection, so he can execute a command on the server. He is on

the same local area network as these two computers. You need to construct a TCP packet

for the attacker. Please fill in the following fields:

Source IP and Destination IP

Source port and Destination port

Sequence number

The TCP data field.

Section $5$: PKI Public Key Infrastructure

I. The following is an X$.509$ certificate.

Certificate:

Data:

Version: $3(02)$

Serial Number:

$3$d:$0$e: $98$:b$2$:bf : af : fa: $9$e: $99$: $91$:$05$:$64$:$69$:$6$e:$11$:$2$a

Signature Algorithm: sha$256$WithRSAEncryption

Issuer: C$=$US$,$ O$=$Symantec Corporation,

OU$=$Symantec Trust Network,

CN$=$Symantec Class $3EV$ SSL CA $-$ G$3$

Validity

Not Before: Aug $1400$:$00$:$002017$ GMT

Not After : Sep $1323$:$59$:$592018$ GMT

Subject: $..$ C C$=$US$/$postalCode$=22230,$ ST$=$Virginia,

$L=$ Arlington$/$street $=4201$WilsonBlvd,

O$=$National Science Foundation, OU$=$DIS,

CN$=$www $.$ nsf $.$ gov

Subject Public Key Info:

Public Key Algorithm: rsaEncryption

Public$-$Key: $(2048$ bit$)$

Modulus :

$00$:$ca$:$fb$:$26$:$78$:$06$:$25$:$b1$:$9e$:$67$:$1d$:$69$:$0b$:$10$:$06$ :

cf: $25$: b$6$: $7$d: de :$8e$:$56$:$80$: e $1$:$1c$:$38$:$52$:$62$:$43$:$fd$ :

$...$

Exponent: $65537(0$x$10001)$

Signature Algorithm: sha$256$WithRSAEncryption

$4$b:$0$d: $62$:$11$:$b4$:$dc$:$78$:$09$:$12$:$c1$:$1b$:$24$:$ff$:$98$:$43$:$58$:$1c$:$54$ :

$0a$:$34$: be: $8$f: $3$f : $12$:$8f$:$17$:$4a$: fe: $5$b:$26$:$13$:$1$a: $5$f:a$7$: $87$:ad:

$...$

ba:$2$c: $10$:$c7$:$bc$:$8b$:$2c$:$15$:$6e$:$0c$:$d2$:$d0$:$8b$:$74$:$52$:$c8$:$ed$:$05$:

ob: $9b$:$62$:$41$

a$)$ Who issues the certificate?

$($b$)$ Who is the owner of the certificate?

$($c$)$ Who generated the signature on this certificate, and how can this signature be verified?

$($d$)$ The public key contained in this certificate is based on the RSA algorithm. Using

the RSA algorithm, to encrypt a message $M,$ we calculate Memodn. What is

the value of $e$ and $n$ in this public key? If a number is too large, you only need to

write down its first four bytes.

$($e$)$ Before issuing the certificate, the CA needs to do a verification regarding the subject

field. Please describe what this verification is$,$ and why it is necessary.