Quesiton 1: The following code fragments show a sequence of virus instructions and a metamor-phic version of the virus. Describe the effect produced by the metamorphic code.
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Original Code
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Metamorphic Code
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mov add call
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eax, eax, [eax]
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5 ebx
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mov push pop add swap swap call nop
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eax, ecx ecx eax, eax, ebx, (eax)
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5
ebx
ebx
eax
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Quesiton 2: What type of malware is the following code fragment?
legitimate code
if data is Friday the 13th;
crash computer(); legitimate code
Quesiton 3: Consider the following fragment in an authentication program and determine what type of malicious software this is.
username = read_usernamen ;
password = read_password0 ;
if username is "133t h4ckOr"
return ALLOW_LOGIN;
if username and password are valid
return ALLOW_LOGIN
else return DENY_LOGIN
Quesiton 4: What is the difference between a packet filtering firewall and a stateful inspection firewall? 12.6 What is an application-level gateway?