Reverse Engineering
- Padma Dasari
Reverse Engineering
Engineering is the profession involved in designing,
manufacturing, constructing, and maintaining of products,
systems, and structures.
The process of duplicating an existing component, subassembly,
or product, without the aid of drawings, documentation, or
computer model is known as reverse engineering.
• Software Reverse engineering is taking apart an
object/program to see how it works in order to duplicate or
enhance the object.
• Technically, Software reverse engineering involves reversing a
program's machine code, into the source code.
Reverse Engineering
Reverse engineering can be viewed as the process of analyzing a
system to:
• Identify the system's components and their interrelationships
• Create representations of the system in another form or a higher
level of abstraction
• Create the physical representation of that system
• physics is an attempt to reverse Engineering the Universe.
• Molecular Biology is an attempt to reverse Engineering the
genetic code.
Why do Reverse Engineering?
• Consider a piece of software for which no one has yet bothered
to write a manual or piece of software with undocumented
features.
• An Artifacts are broken and we want to understand its structure
so we can fix it.
• An Artifacts is old and clunky and want to replace with newer
and sleeker version.
• Want to steal/replicate our competitors’ ideas.
Reverse Engineering
Analyze piece of code in order to figure out how expensive it would be
to make some proposed change.
we can use two techniques.
1. Hierarchical Regular Expression
2. Island grammars.
Hierarchical Regular Expression
Hierarchical Regular Expression
– Lightweight analysis
– Regular Expression
• (aUb)* aaabba (aUb)*
Hierarchical Regular Expression
 [ <type> ] <functionName> \ ( [ {<formalArg> }1 ] \ ) [ {
<type> <argDecl> ; }1 ] \{
<calledFunctionName> \ ( [ { <parm> }1 ] \)
Is it legal? What are reasons!!
Reasons for reverse engineering a part or product:
• The original manufacturer of a product no longer produces a
product
• There is inadequate documentation of the original design
• The original manufacturer no longer exists, but a customer
needs the product
• The original design documentation has been lost or never
existed
• Some bad features of a product need to be designed out.
• To strengthen the good features of a product based on longterm usage of the product
• To analyze the good and bad features of competitors' product
Instant Messaging or IM
Instant Messaging:
The instant messaging marketplace is current fragmented among
a lot of different networks:
• AOL Instant Messenger
• MSN Messenger
• Yahoo Messenger
• Google Talk and
• others.
IM: [No] Networking
Although these IM companies have periodically discussed making
their networks interoperable, at present none of them are, despite
the fact that they’ve been on the market for years.
Ex: AOL, Yahoo, MSN has been there for years and no sharing
among these networks.
Needs many IM applications instead of one application software
-Software reverse engineering come to rescue.
Reverse Engineering
Reasons for reverse engineering a part or product:
• An open source project called Fire built a Mac OS X
application that can access all four networks (and some
others). That means that I can run one program and have
access to all four networks
Details about Fire software can be found at
http://fire.sourceforge.net/
Scientific Methods- Steps
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The Compilation Process
Gathering Info
Determining Program Behavior
Determining Interesting Functions
Understanding Assembly
Debugging
Executable formats
Code Modification
Network Application Interception
Tools