A few years back, TV viewers in Germany were shown how an unsuspecting Internet user, who had accessed a seemingly innocuous Web site, had his own hard disk looked at and actu- ally modified by that Web site! In particular, the seemingly innocuous Web site searched the unsuspecting Internet user’s hard disk, found that he was using a particular software for online banking, and remotely modified its “to do” list. The next time the unsuspecting user connected to his bank with that software for his regular online banking session, unbeknownst to him, he directed his bank to make a payment to the account of the hackers running that seemingly innocuous Web site he had browsed a few days earlier.
There are numerous ways whereby the files in one’s com- puters can be viewed, changed, or deleted by a remote third party if one is connected to the Internet. Some of these involve remote hacking through any one of a multitude of security weaknesses in Windows and Windows applications software. Others use adware (a.k.a. spyware) installed by unsuspecting users of assorted software packages that call (their) home and report on a user’s hard disk contents (see Chapter 9, particu- larly Section 9.19). Still others use commercial keystroke- capture software or hardware that also calls home and reports on a user’s keyboard strokes (see Sections 4.3 and 4.4). Still others exploit one’s use of wireless Wi-Fi connectivity (see Sec- tion 13.2). The list goes on and on.
Unless one has plugged each and every possible way that information can be remotely accessed from one’s computer, one’s computer files can be read, modified, deleted, or even added to without one’s knowledge. “But I am using a firewall, and this cannot happen to me,” one might say. Not true in most cases! Despite its name, a firewall is not an impenetrable barrier; depending on just exactly what it does and how it is configured, its protection could range from none to some (see
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7
Contents
7.1 Protection from which of many online threats? 7.2 Installation of Windows
for secure online operation
7.3 Online security threats and issues
7.4 Software to enhance online security 7.5 Basic do’s and don’ts
Section 9.18). Firewalls are, at best, permeable membranes that can be exploited; some enterprising software programs, for example, try to avoid detection of their surreptitious access to the Internet by timing it to coincide with times that one is already sending data to the Internet through the Web browser (port 80). Others masquerade as legitimate-sounding system soft- ware so that when one’s firewall asks the user for permission for what seems like a legitimate system function to access the Internet, most users will readily grant it on a permanent basis, incorrectly assuming that this access is legitimate and innocuous.
Chapters 7 through 9 will expose the most common ways whereby one’s privacy can be compromised while online and spell out specific ways of defeating those threats to one’s security and privacy. The reader must appreciate, however, that different ways of compromising one’s privacy online can easily be developed and that there is really no future-proof way of positively ensuring that one can never have his or her files looked at, modified, or deleted by unauthorized others from afar. One must stay cur- rent with evolving threats and take the appropriate countermeasures in the future.
It is for this reason that a security-minded user is advised to use two dif- ferent computers: The “good” one should never be connected online. The other one can be inexpensive; it should be used only for online connection and should contain nothing sensitive.
Both computers should be subjected to the same security-related proce- dures detailed in this book to ensure confidentiality of private informa- tion. The computer reserved for online use should be subjected to additional precautions (detailed later in this chapter) because it is vulnerable not only to physical forensics but also to unauthorized online access of its contents. As an example, encrypting the entire hard disk (an option strongly recommended in Section 6.4.1) is totally ineffective for an online computer because the disk has to be functioning in its decrypted state while online.
Any data to be transferred between these two computers (e.g., a recently downloaded file intended for the offline computer) could easily be trans- ferred through a removable disk (e.g., floppy, Zip, USB key).
Alternately, one can opt for having a single computer with removable, bootable hard disks so that one can boot with and use one disk for secure offline use and another disk for risky online use. Removable, bootable drive mounts are available for conventional hard disk drives.
Adding security-related protective measures always results in varying degrees of inconvenience, much like having a lock on one’s front door results in the inconvenience of having to carry a key and unlock the door each time one wants to enter. Each user will have to decide for him- or her- self whether the security benefits derived from each of the detailed steps recommended in the rest of this chapter are worth the associated inconven- ience they introduce. Such a decision can only be made personally because each individual has different security needs: A freedom fighter in a repres- sive regime has different security needs from a teenager in a free society
who uses his or her computer mostly to play computer games and who never uses it online.
7.1
Protection from which of many online threats?
The importance of answering this question up front cannot be overempha- sized. In normal life, too, one takes different protective measures outdoors to protect one’s self from, say, malaria carrying mosquitoes as opposed to pickpockets as opposed to heavy rain.
One’s privacy is exposed online to the following threats:
1. Malicious remote Web sites that attempt to read (or write to) one’s hard disk from afar;
2. Adware installed on one’s computer that calls home;
3. Commercial keystroke-capturing software/hardware that calls home;
4. Remote attempts to hack into one’s computer from afar;
5. A nosy ISP;
6. A tap on one’s telephone by a private detective or other entity;
7. A hostile virus/Trojan/worm.
Each threat requires a different set of protective measures. Most protec- tive measures can work in conjunction with each other.
It must also be appreciated that some protective measures may raise one’s profile and, in essence, invite even more intrusiveness and inquisitive- ness into one’s affairs. An individual who prances around a disreputa- ble part of town with a briefcase visibly handcuffed to his hand is inviting far more unwanted attention and trouble than the same person dressed in clothes that match the environment and carrying whatever it is he or she is carrying in a concealed pocket. Similarly, an online computer user in a totalitarian regime would be unwise to connect with a fully encrypted connection as a matter of principle just to browse the latest posting of antique furniture on Ebay. Each security-conscious user will have to use good judgment and common sense in deciding what technical security, if any, to use.