Re: Linux Swap Partitions

From: Samuel R.Baskinger (samuelat_private)
Date: Sun Jul 28 2002 - 12:58:46 PDT

  • Next message: Seth Arnold: "Re: Linux Swap Partitions"

    Hey Rick (and all),
    
    	The swap partition is a component of the virtual memory system in 
    Unix and Unix-like system.  When something doesn't "fit" into the actual 
    RAM the computer has, the operating system can page out individual pages 
    of memory it is not using to the hard disk (specifically to the swap 
    partition).  If memory is in particularly high demand and a whole 
    process has been deemed idle, that whole process may be swapped out of 
    the RAM and onto the virtual memory (again, the swap partition).
    	Essentially the swap partition is scratch paper for when memory 
    gets tight.  Swap space also has virtually no format as it's state is 
    kept in RAM by the OS.  If the computer crashes, the meaning of all 
    those bits on the swap space become meaningless to the computer because 
    the mappings in memory and the CPU are gone.
    	So what of all this can you use? Well, most computer do not wipe or 
    protect the swap partition by zeroing pages on it.  This means that *if* 
    a file was swapped or paged out of memory and into virtual memory, then 
    it *might* still be there.
    	In my opinion, swap space is a reasonable route to run down if you 
    are having a hard time with other routes, provided the system is a 
    single user system and you have an idea of what you are looking for.  If 
    the system is multi user, you may have a hard time linking some 
    arbitrary bits in the swap partition to a particular user.  You need to 
    have an idea of what you are looking for because, well, swap partitions 
    are very big for a human to look at.  You need some automation that can 
    flag parts that are interesting.
    	Hope this helps somewhat!  I wish I could tell you how to mount and 
    peek around the swap partition, but I don't know the details of it off 
    the top of my head.
    
    Sam B.
    
    
    On Wednesday, July 24, 2002, at 02:38 PM, saliskorat_private wrote:
    
    >
    >
    > New to forensics.... particularly in Unix/Linux...
    >
    > I have imaged the partitions on a problematic Linux box, ending up with,
    > among other things, a swap partition. My question is:
    >
    > Is there any value to mounting and analysing a linux swap partition ? I
    > attempted to mount and received an error, stating that the partition
    > appeared to be a swap partition - which of course it was.
    >
    > If there is value in mounting and analysing, is there a particular -t
    > parameter for mounting a swap file system? What should I be looking for
    > once i get it mounted ?
    >
    > Thanks in advance for any suggestions or advice.
    >
    > Rick
    >
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