Difference between pages "VPN" and "Windows SuperFetch Format"

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(Overview)
 
(File header)
 
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'''VPN''' (Virtual Private Network) is a class of technology that allows remote machines to interconnect by creating a virtual network layer, on top of the physical network connection, that in practice is used to maintain the privacy of data shared over this virtual network connection (essentially all VPN toolsets use some form of packet-level [[encryption]]). There are many different modern implementations of the VPN concept itself, to the point where categorizing them together becomes somewhat questionable.  
+
== MEMO file ==
 +
Some of the <tt>Ag*.db</tt> files are MEMO files.
  
== Overview ==
+
The MEMO file consists of:
 +
* file header
 +
* compressed blocks
  
Virtual Private Networks are deployed by organizations and individuals for different purposes:
+
=== File header ===
 +
The file header is 84 bytes of size and consists of:
 +
{| class="wikitable"
 +
|-
 +
! Offset
 +
! Size
 +
! Value
 +
! Description
 +
|-
 +
| 0
 +
| 4
 +
| 0x304D454D ("MEM0") or 0x4F4D454D ("MEMO")
 +
| Signature
 +
|-
 +
| 4
 +
| 4
 +
|
 +
| Uncompressed (total) data size
 +
|-
 +
|}
  
* Protecting confidential information in organizations, when connecting geographically distant office networks;
+
=== Compressed blocks ===
* Providing "work from home" or traveling employees with secure remote access to office network resources;
+
The file header is followed by compressed blocks:
* Securing general Internet traffic in particularly insecure network usage settings (e.g. open wireless networks);
+
{| class="wikitable"
* Encrypting all internet traffic to and from a home connection, to prevent ISP packet shaping and/or surveillance (i.e. [http://www.torrentfreedom.net Torrentfreedom Privacy].
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|-
 +
! Offset
 +
! Size
 +
! Value
 +
! Description
 +
|-
 +
| 0
 +
| 4
 +
|
 +
| Compressed data size
 +
|-
 +
| 4
 +
| ...
 +
|
 +
| Compressed data
 +
|-
 +
|}
  
When used for Internet connectivity, VPN service also acts as a form of proxy and protects the user's physical IP address from public display. As a result, they are an increasingly popular form of anonymity protection for internet users. While there are some concerns that the availability of anonymous connectivity would encourage true fraud, in practice those engaged in commercial fraud online use other, existing tools to keep their activities from being discovered - there is no known case of a commercial VPN service being used to further a fraudulent activity online, thus far.
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=== Uncompressed data ===
 +
<b>TODO</b>
  
== VPNs and anonymity ==
+
== TRX file ==
 +
The <tt>Ag*.db.trx</tt> files are TRX files.
  
* Log files: VPN services may maintain usage logs which could then be used to track the activities of the user of those services, after the fact. However some commercial consumer-oriented VPN services specifically configure their servers not to retain any logfile information of this type. An example is [[Cryptocloud_VPN]].
+
<b>Note that the following format specification is incomplete.</b>
  
* Protocol stack: [[TCP timestamps]] and IP ID values may be used in correlating incoming (encrypted) and outgoing (unencrypted) network streams. This type of "traffic analysis" can, in theory, be used to gather information about a fully-encrypted VPN connection - in practice, there are no known examples of traffic analysis being used against commercial VPN service providers.
+
=== File header ===
 +
The file header is 84 bytes of size and consists of:
 +
{| class="wikitable"
 +
|-
 +
! Offset
 +
! Size
 +
! Value
 +
! Description
 +
|-
 +
| 0
 +
| 4
 +
| 1
 +
| Unknown (Version?)
 +
|-
 +
| 4
 +
| 4
 +
|
 +
| Unknown
 +
|-
 +
| 8
 +
| 4
 +
|
 +
| File size
 +
|-
 +
| 12
 +
| 4
 +
|
 +
| Unknown (Record count?)
 +
|-
 +
| 16
 +
| 4
 +
|
 +
| Unknown (Record count?)
 +
|-
 +
| 20
 +
| 4
 +
|
 +
| Unknown (Records offset or file header size)
 +
|-
 +
|}
  
 
== See Also ==
 
== See Also ==
 +
* [[SuperFetch]]
  
* [[Cryptocloud VPN]]
+
== External Links ==
* [[Tor]]
+
* [http://blog.rewolf.pl/blog/?p=214 Windows SuperFetch file format – partial specification], by ReWolf, October 5, 2011
* [[Proxy server]]
+
  
[[Category:Anti-Forensics]]
+
[[Category:File Formats]]
[[Category:Network Forensics]]
+
[[Category:Encryption]]
+

Revision as of 00:28, 15 April 2014

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Contents

MEMO file

Some of the Ag*.db files are MEMO files.

The MEMO file consists of:

  • file header
  • compressed blocks

File header

The file header is 84 bytes of size and consists of:

Offset Size Value Description
0 4 0x304D454D ("MEM0") or 0x4F4D454D ("MEMO") Signature
4 4 Uncompressed (total) data size

Compressed blocks

The file header is followed by compressed blocks:

Offset Size Value Description
0 4 Compressed data size
4 ... Compressed data

Uncompressed data

TODO

TRX file

The Ag*.db.trx files are TRX files.

Note that the following format specification is incomplete.

File header

The file header is 84 bytes of size and consists of:

Offset Size Value Description
0 4 1 Unknown (Version?)
4 4 Unknown
8 4 File size
12 4 Unknown (Record count?)
16 4 Unknown (Record count?)
20 4 Unknown (Records offset or file header size)

See Also

External Links