Antedating: Creating a document with incorrect time stamps.
Investigation:

• Analyzing the metadata of the document to get the baseline information is the first step.
• Secondly, perform a comparative analysis of the metadata of all the documents under the investigation.
• One might get some important information from the source machine. Analyze the event logs if it's a windows machine.
• Look for the email headers if the document is shared via email.
  
• Use basic common sense in analysis by looking and the OS and the release date of the extension.

How to antedate a document?

• Use Software to change the metadata.
• Changing the computer time before creating an electronic document is another method of antedating, as the metadata for the newly created electronic file will be based on the incorrect setting of the system.
  

Readings:
http://www.cse.scu.edu/~tschwarz/COEN252_13/Papers/antedating.pdf
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​http://www.theglobaldispatch.com/digital-forensics-and-the-fbi-how-todays-tech-will-help-solve-hillarys-email-investigation-55389/

Let me try to list down some of the things that a Incident response team will lose volatile data if they turn off the suspect's machine.
1) Logged in Users
2) TCP Connections
​3) Running Processes

​Network Forensics: It’s basically sniffing, recording, acquisition, and analysis of network traffic and event logs in order to investigate security.
It can reveal many things like, Source of security incidents and attacks, Path of attack, Techniques used by attacker.
Types of network addressing scheme:

• Lan Addressing: Each node of a LAN has a MAC address. Data packets are directed to either one of the nodes or all notes.
• Internet addressing: Internet address is a combination of network and node address. IP is responsible for network layer addressing in the TCP/IP protocol.

What is IDS?
Intrusion detection System gathers and analyzes information.
Types:

• Network based: It’s a black box places in a network, listening to the pattern in a indicative way.
• Host Based: Includes auditing the events that occur on a specific host.
• Log File monitoring: Parse log file after events has already occurred.
• File Integrity Checking: Checks for Trojan Horses or files.

Honeypots:
As name suggest, it’s set to attract and trap people.
Network Attacks:
IP Address Spoofing: Attacker changes his/her IP address to hide identity.
Man in the middle attack: It’s intrudes into an existing connection between systems and to intercept messages being exchanged.
Packet sniffing: An attacker can capture the packet by putting a packet sniffer on the network.
Buffer Overflow: Buffer overrun in the stack space. Attacker inject malicious code on the stack and overflows it to overwrite in return pointer so that the flow of control switches to the malicious code.
New line injection attack: Attacker inject plaintext into the log file.

Computer Security logs – contains information about events in an organizational and network

1. OS Logs -  Logs of OS for server, workstation and network device

i.Event logs: Operational Action by OS
ii.Audit Logs: Security event information like failed auth, file access, policy changes, account changes

1. Application Logs: All events logs by Program, email server, database server.
2. Security Logs: Logs of network host based security software log like antivirus logs and all security related logs.

Router log file:

• Store logs in router cache
• Detailed info about the network traffic

Honeypot logs:

• Logs from Honeypots are considered as suspicious
• The honey pot admin is the only authorized user.

Application Logs: Application logs store event messages recorded by windows application.
Popular Event ID’s

• 528 – Successful Logged on to an account
• 531 Logon attempt made by disable account
• 532 – Expired account

Port number:
UDP Port 123- NTP
Event Correlation Approaches:

• Graph Based:
• Netural Network based
• Codebook-based
• Rule based:
• Field-Based:
• Automated Field:
• Payload Correlation:

Types of Correlation:

• Same Platform Correlation
• Cross Platform Correlation

What is Steganography?
Hiding a secret message within an ordinary message and extracting it at the destination to maintain confidentiality of the data.
Example: Popular method is hiding a file inside an image or using image file as a cover.
http://www.wikihow.com/Hide-a-File-in-an-Image-File
Techniques:

• Substitution Techniques
• Transform Domain Techniques
• Cover Generation Techniques
• Spread Spectrum Techniques
• Distortion Techniques
• Statistical Techniques

Classification:
Technical Steganography:
Uses physical and chemical means to hide the existence of a message.Example – Invisible ink, Microdots, In Computers (Uses redundant information in pictures, text, sound etc)
Linguistic Steganography:
Uses written natural language to hide the message in the carrier in some non-obvious ways.

1. Semagrams – Uses visual symbols or signs. Further classified into visual(Eg Doodles) or Text semagrams (small changes in font size, color etc)
2. Open codes – Hide in a specifically designed patter – unclear to the normal user.
   1. Jargon Code- Only a group of people  can understand
   2. Covered Ciphers (Null Ciphers and Grille Cipher): Hidden openly in the carrier medium.

Windows Forensics:
Cache Memory and History Analysis:
IE:

• Content.IE5 Files – Temporary internet files
• AppData Folders – Contain Cookies
• History Folder

IE Cookies View Tool – for Analysis
Firefox:
Md5 Hash

• 32 digit -128 bit Message digest
• Non collision resistant
• Checks the integrity of the tool

Recycle Bin:

• File is deleted – Sub Directory is created
• Recycler
• Remember Convention for Recycler <Drive Name – Hash>
• Info2 contains the records related to the data.

Restore Points:

• RP.Log filename

Change.log.x files

• Format: Axxxxx.ext
• X is sequence number and ext is extension of the file.

Prefetch:

• Prefetch files leaves traces and can collect data from it.

Shortcut Files

• Use .lnk files

File Signature Analysis:

• Collect information from first 20 bytes of a file
• Mac Time Stamp: Modification, Access and Change time. Managed by OS  in UTC Format

Static Analysis

• You’ll not open the file- Just open it in some application and review the data.

Dynamic Analysis:

• You'll execute the file in order to analyze it.
• Create a Test Environment and Process of Testing malware

Meta Data investigation:

• Data about data
• Descriptive Metadata
• Structural Metadata

Windows Events:

• Logs Day to day  Events
• Event log maintains this data.
• Command – wevtutil
• Events files are databases- related to System, Security and Application
  
• Storage location: SysEvent.evt
  

Popular event ID:

• Event ID 4902 – Modification of Audit Policy

ISS Log:

• Exyymmdd.log
• Ex refers to extended format

DHCP Server Logs:

• Format

Firewall Logs:
                Pfirewall.log
Windows Password:
Active Directory - NTDS.DID –
For a System is SAM (System Account Manager) File – System32 Config, Additional Copy in repair folder.

• Password is stored in HASH format

LMNAM –it’s outdates
NTLM V2 is the latest version used by windows:
Sigverif:  Shows unsigned drivers

• CurrPorts – Similar to NetStat -a

 
 
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