1587: COMMUNICATION SYSTEMS 1Introduction to Security

Dr. George Loukas

University of Greenwich, 2014-2015

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NCZW VUSX PNYM INHZ XMQX SFWX WLKJ AHSH NMCO CCAK UQPM KCSM HKSE INJU SBLK IOSX CKUB HMLL XCSJ USRR DVKO HULX WCCB GVLI YXEO AHXR HKKF VDRE WEZL XOBA FGYU JQUK GRTV UKAM EURB VEKS UHHV OYHA BCJW MAKL FKLM YFVN RIZR VVRT KOFD ANJM OLBG FFLE OPRG TFLV RHOW OPBE KVWM UQFM PWPA RMFH AGKX IIBG

FORCED TO SUBMERGE DURING ATTACK, DEPTH CHARGES.LAST ENEMY LOCATION 08:30, NAVAL GRID AJ 9863, 220 DEGREES, 8 NAUTICAL MILESI AM FOLLOWING THE ENEMYBAROMETER 1014 MILLIBAR TENDENCY FALLING, NORTH NORTH EAST 4, VISIBILITY 10.

AHXR VUSX PNYM INHZ XMQX SFBX BLKJ AHSH NMCO CCAK UQPM KCSM HKSE INJU SBLK IOSX CKUB HMLL XCSJ USRR DVKO HULX TCCB GVLI YXEO BCZA HKKF VDRE CEZL XOBA FGYU JQUK GRTV UKAM EURB VEKS UHHV OYHA BCJU MAKL FKLM YFVN RIZR VVRT KOFD ANJM OLBG FFLE OPRG TFLV RHOM OPBE KVJM UQFM PLPA RMFH AGKX IIBG ABLT STIE ANFQ LOTZ LPTR OURE JVMR SDAL PITC ZSET LGSO HPIY QTLF HCOT PATG HUVX LOUS MEAP DLEF NSQZ MYTR OIFD HGYC SPGO ZEOP GJSL BNDM TYLA FSLV ZBJA

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500 BCSkytale 9th century

Al-Kindi1918

(enigma machine)

1976(Public-Key

cryptography)

CRYPTOGRAPHY

Cryptography

Single-key cryptographyAlso known as symmetric cryptography.

A binary message is encrypted and decrypted using the same secret key.The simplest type of binary encryption/decryption is to XOR each bit of the message with the secret key.

XOR =XOR =XOR =

logicalXOR

Message 1010100101010011010110 Key 0110011001010100110001

Encrypted message 1100111100000111100111

XOR

Cryptographic exerciseXOR =XOR =XOR =

logicalXOR

The hacker is looking for the solutions to the mock test. She knows the approximate format of the URL because that’s what George uses most of the time: http://staffweb.cms.gre.ac.uk/~lg47/lectures/COMP1587/COMP1587-MockTest2014-XXXX.docx She found the XXXX part but encrypted: 00010000 00010100 00011011 00010010 The encryption function is XOR. What is the XXXX part if the key is 01110101?

01101110 0110011101110101 01110101 01110101 01110101XOR00010000 00010100 00011011 00010010

01100101

e01100001

a s ya = 01100001 f = 01100110 k = 01101011 p = 01110000 u = 01110101 z = 01111010b = 01100010 g = 01100111 l = 01101100 q = 01110001 v = 01110110

ASCII TABLE OF CHARACTERS

c = 01100011 h = 01101000 m = 01101101

r = 01110010 w = 01110111

d = 01100100 i = 01101001 n = 01101110 s = 01110011 x = 01111000e = 01100101 j = 01101010 o = 01101111 t = 01110100 y = 01111001

Confidentiality

CONFIDENTIALITY

IntegrityJan. 2010: Spanish PM’s website defaced

June 2010: Stuxnet

CONFIDENTIALITY INTEGRITY

A computer program that altered the motor speeds of an Iranian nuclear facility’s centrifuges.

A common method is to use Cross-site Scripting (XSS)

<script>document.body.background="http://your_image.jpg";</script>

Availability2004: US businessman hires hackers to launch Denial of Service attacks against competitors. $2 million in losses.

2002: UK teenager disables Port of Houston web systems accidentally, while trying to take cyber-revenge over a girl.

2000: Canadian teenager knocks offline Amazon, yahoo, CNN, eBay ….

2008: Georgia accuses Russia of coordinated availability attacks, coinciding with military operations in South Ossetia.

2007: Estonian parliament, newspapers and banks are knocked offline by Russian hacktivists over a political issue

CONFIDENTIALITY INTEGRITY AVAILABILITY

Lately: The group Anonymous have been launching availability attacks for political purposes

A Denial of Service attack (DoS) is any intended attempt to prevent legitimate users from reaching a specific network resource.G. Loukas and G. Oke. Protection Against Denial of Service Attacks: A Survey. Comp. Journal, 53(7): 1020-1037, 2010

Example DoS: Reflector attack• Send packets to

several computers pretending to be the target

• When they reply, they all send ACK packets to the target

G. Loukas and G. Oke. Protection Against Denial of Service Attacks: A Survey. Comp. Journal, 53(7): 1020-1037, 2010

A Denial of Service attack (DoS) is any intended attempt to prevent legitimate users from reaching a specific network resource.

CONFIDENTIALITY INTEGRITY AVAILABILITY

Availability Attack Countermeasures

CONFIDENTIALITY INTEGRITY AVAILABILITY

• Replace network components with greater capacity ones

• Redundancy and diversity (more servers, links, nodes etc.)

• Detect attack traffic and filter it out

• Honeypots (to redirect attack to fake targets)

Common countermeasures

CONFIDENTIALITY INTEGRITY

Detect unauthorised access

Detect and remove malicious software

Block/filter connections to critical systems

Protect real users by attracting attacks to fake users

Set strict rules for users to reduce security breaches

Cyber-physical attacks

Underlying causes of security failures Monopolies present juicy targets. A single vulnerability affects

millions of people

Deficit of computer security experts in the market

Strong at Windows, Linux and network technologiesAbility to think adversariallyAbility to adapt/learn constantlyWriting well-structured and clear reportsWorking in teams

Job adverts

online today

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Malware analysisJoanna Rutkowska, Invisible Things Lab

White hat hacker, Google“Security Princess” Parisa Tabriz

Director of Technology StrategyJames Lyne, Sophos