1. 1 The Attack and Defense of Computers Dr. 許 富 皓

2. 2 Malware

3. 3 Malicious Software (Malware): Security tools and toolkits Back doors (trap doors) Logic bombs Viruses Worms Binders Droppers Trojan Horses Bacteria or rabbit programs. Spyware Rootkit URL Injection Dialers

4. 4 Security Tools and toolkits Automatically scan for computer security weaknesses. Can be used by both security professionals and attackers. E.g. Nessus, COPS, ISS, Tiger, … and so on. Nessus ISS There are also programs and tool sets whose only function is to attack computers. Script kids P.S. These tools may damage the systems that install them or may contain booby-trap that will compromise the systems that install them.

5. 5 Logic Bombs A logic bomb is a piece of code intentionally inserted into a software system that will set off a malicious function when specified conditions are met. For example, a programmer may hide a piece of code that starts deleting files, should he ever leave the company (and the salary database). Usually written by inner programmers.

6. 6 Logic Bombs and Viruses and Worms Software that is inherently malicious, such as viruses and worms, often contain logic bombs that execute a certain payload at a pre-defined time or when some other condition is met. This technique can be used by a virus or worm to gain momentum and spread before being noticed. Many viruses attack their host systems on specific dates, such as Friday the 13th or April Fool's Day. Trojans that activate on certain dates are often called "time bombs".

7. 7 Key Logger A program or hardware device that captures every key depression on the computer. Also known as "Keystroke Cops," they are used to monitor a user's activities by recording every keystroke the user makes, including typos, backspacing and retyping.

8. 8 Security Concerns about Key Loggers Keystroke logging can be achieved by both hardware and software means. There is no easy way to prevent keylogging software being installed on your PC, as it is usually done by a method of stealth. If you are using a home PC, then it is likely to be free on any keystroke logging hardware (but remember there may be keystroke logging software). Try and avoid typing private details on public PCs, and always try and avoid visiting sites on public PCs that require you to enter your login details, e.g. An online banking account.

9. 9 Example Ardamax Keylogger [1][2]12

10. 10 Dialers A program that replaces the phone number in a modern’s dial-up connection with a long distance number, often out of the country, in order to run up phone charges on pay- per-dial numbers dials out at night to send keylogger or other information to an attacker.

11. 11 URL Injection Change the URL submitted to a server belonging to some or all domains.

12. 12 Bacteria and Rabbits Bacteria (also known as rabbit programs) are a type of malware that create many instances of themselves, or run many times simultaneously, in order to consume large amounts of system resources. Bacteria create a denial of service effect as legitimate programs may no longer be able to run, or at least may not run properly.

13. 13 Binder [CA]CA

14. 14 Definition of Binder Binder A tool that combines two or more files into a single file, usually for the purpose of hiding one of them. A binder compiles the list of files that you select into one host file, which you can rename. A host file is a simple custom compiled program that will decompress and launch the embedded programs. When you start the host, the embedded files in it are automatically decompressed and launched.

15. 15 Example When a Trojan is bound with Notepad, for instance, the result will appear to be Notepad, and appear to run like Notepad, but the Trojan will also be run.

16. 16 Program YABYAB: Yet Another Binder User Guide

17. 17 Dropper [Wikipedia]Wikipedia

18. 18 Definition of a Dropper A dropper is a program (malware component) that has been designed to "install" some sort of malware (virus, backdoor, etc) to a target system. Single stage: the malware code can be contained within the dropper in such a way as to avoid detection by virus scanners Two stages: the dropper may download the malware to the target machine once activated

19. 19 Types of Droppers There are two major types of droppers: those that do not require user interaction perform through the exploitation of a system by some vulnerability those that require user interaction by convincing the user that it is some legitimate or benign program.

20. 20 Examples 8sec!Trojan

21. 21 Trojan Horse [Wikipedia]Wikipedia

22. 22 Trojan Horse In the context of computer software, a Trojan horse is a malicious program that is disguised as or embedded within legitimate software. Trojans use false and fake names to trick users into executing them. These strategies are often collectively termed social engineering. A Trojan is designed to operate with functions unknown to the victim. In most cases the program performs other, undesired functions, but not always. The useful, or seemingly useful, functions serve as camouflage for these undesired functions.

23. 23 Properties of Trojan Horses Trojan horse programs cannot operate autonomously, in contrast to some other types of malware, like worms. Just as the Greeks needed the Trojans to bring the horse inside for their plan to work, Trojan horse programs depend on actions by the intended victims if Trojans replicate and even distribute themselves, each new victim must run the program/Trojan. Due to the above reasons Trojan horses’ virulence depends on: successful implementation of social engineering concepts not flaws in a computer system's security design or configuration.

24. 24 Categories of Trojan Horses There are two common types of Trojan horses: an otherwise useful software that has been corrupted by a cracker inserting malicious code that executes while the program is used. Examples include various implementations of  weather alerting programs  computer clock setting software  peer to peer file sharing utilities. a standalone program that masquerades as something else, like a game or image file (e.g. firework.jpg.exe in Windows.)

25. 25 Malware Parasitizes inside Trojan Horses In practice, Trojan Horses in the wild often contain: spying functions (such as a packet sniffer) backdoor functions that allow a computer, unbeknownst to the owner, to be remotely controlled from the network, creating a zombie computer. The Sony/BMG rootkit Trojan, distributed on millions of music CDs through 2005, did both of these things. Because Trojan horses often have these harmful behaviors, there often arises the misunderstanding that such functions define a Trojan Horse.

26. 26 Example of a Simple Trojan Horse A simple example of a Trojan horse would be a program named waterfalls.scr.exe claiming to be a free waterfall screensaver which, when run, instead begins erasing all the files on the computer.

27. 27 E-Mail Trojan Horses On the Microsoft Windows platform, an attacker might attach a Trojan horse with an innocent-looking filename to an email message which entices the recipient into opening the file. The Trojan horse itself would typically be a Windows executable program file, and thus must have an executable filename extension such as.exe,.com,.scr,.bat, or.pif. Since Windows is sometimes configured by default to hide filename extensions from a user, the Trojan horse has an extension that might be "masked" by giving it a name such as Readme.txt.exe. With file extensions hidden, the user would only see Readme.txt and could mistake it for a harmless text file. Icons can also be chosen to imitate the icon associated with a different and benign program, or file type.

28. 28 Commonly Used Methods of Infection Websites. E-mails. Downloaded Files.

29. 29 Websites You can be infected by visiting a rogue website. Internet Explorer is most often targeted by makers of Trojans and other pests, because it contains numerous bugs, some of which improperly handle data (such as HTML or images) by executing it as a legitimate program. (Attackers who find such vulnerabilities can then specially craft a bit of malformed data so that it contains a valid program to do their bidding.) The more "features" a web browser has (for example ActiveX objects, and some older versions of Flash or Java), the higher your risk of having security holes that can be exploited by a Trojan horse.

30. 30 Example 1: Microsoft IE window() Arbitrary Code Execution Vulnerability [Secunia]Secunia The vulnerability is caused due to certain objects not being initialized correctly when the window() function is used in conjunction with the event. This can be exploited to execute arbitrary code on a vulnerable browser via some specially crafted JavaScript code called directly when a site has been loaded. Example: Successful exploitation requires that the user is e.g. tricked into visiting a malicious website. PROOF OF CONCEPT

31. 31 Explanation [Computer Terrorism]Computer Terrorism

32. 32 [HTML Code Tutorial]HTML Code Tutorial The browser triggers onLoad when the document is finished loading. The contents of onLoad is one or more JavaScript commands. So, for example, the following tag tells the browser to bring up an alert box once the page is completely loaded:

33. 33 MS IE - Crash on JavaScript window() - calling (1) There is a bug in Microsoft Internet Explorer, which causes a crash in it. The bug occurs, because Microsoft Internet Explorer can't handle a call to a JavaScript-function with the name of the " window "-object. An object used in Javascript.object

34. 34 MS IE - Crash on JavaScript window() - calling (2) [symantic]symantic Internet Explorer fails to properly initialize the JavaScript ` Window() ' function. When the ' onLoad ' handler is set to call the improperly initialized ` Window() ' function, the Web browser attempts to call the address 0x006F005B, which is derived from the Unicode representation of ' OBJECT '. CALL DWORD [ECX+8] It is shown that JavaScript prompt boxes can be used by attackers to fill the memory region at 0x00600000 with attacker-supplied data, allowing executable machine code to be placed into the required address space. 1.Crash, if pointing to non-code. 2.Execution, if pointing to code.

35. 35 Dangerous Web Site The web site pointed by the following URL is one containing the trap described in the previous slides. HTTP MSIE JavaScript OnLoad Rte CodeExec [symantic]symantic http://marc.theaimsgroup.com/?l=bugtraq&m=111746394106172&w=2

36. 36 Example 2: Trojan Downloader [F-Secure][Microsoft]F-SecureMicrosoft Trojan downloader is usually a standalone program that attempts to secretly download and run other files from remote web and ftp sites. Usually Trojan downloaders download different Trojans and backdoors activate them on an affected system without user's approval. Trojan downloader, when run, usually installs itself to system and waits until Internet connection becomes available. After that it attempts to connect to a web or ftp site, download specific file or files and run them.

37. 37 Example 3: Trojan Horse Exploits Image Flaw [Declan McCullagh et al.] EasyNews, a provider of Usenet newsgroups, said it has identified two JPEG images that take advantage of a previously identified flaw ( a heap- based buffer overflow [Michael Cobb] ) in the way Microsoft software handles graphics files.previously identified flawMichael Cobb Windows users could have their computers infected merely by opening one of those Trojan horse images. Attackers tried to use these JPEGs to download Trojan (horse programs) to vulnerable computers.

38. 38 Example 4: Comprise a Web Server and Add Hidden Download Instructions in Web Pages Create frame with size 0.

39. 39 Emails and Trojan Horses The majority of Trojan horse infections occur because the user was tricked into running an infected program. This is why you're not supposed to open unexpected attachments on emails -- the program is often a cute animation or a sexy picture, but behind the scenes it infects the computer with a Trojan or virus.

40. 40 Microsoft Outlook If you use Microsoft Outlook, you're vulnerable to many of the same problems that Internet Explorer has, even if you don't use IE directly. The same vulnerabilities exist since Outlook allows email to contain HTML and images (and actually uses much of the same code to process these as Internet Explorer).

41. 41 Downloaded Files The infected program doesn't have to arrive via email, though; it can be sent to you in an Instant Message downloaded from a Web site or by FTP delivered on a CD or floppy disk

42. 42 Precautions against Trojan Horses (1) Trojan Horses are most commonly spread through an e-mail, much like other types of common viruses. The only difference being of course is that a Trojan Horse is hidden. The best ways to protect yourself and your company from Trojan Horses are as follows: If you receive e-mail from someone that you do not know or you receive an unknown attachment never open it right away. As an e-mail user you should confirm the source. Some hackers have the ability to steal an address books so if you see e-mail from someone you know that does not necessarily make it safe.

43. 43 Precautions against Trojan Horses (2) When setting up your e-mail client make sure that you have the settings so that attachments do not open automatically. Some e-mail clients come ready with an anti-virus program that scans any attachments before they are opened. If your client does not come with this it would be best to purchase on or download one for free. Make sure your computer has an anti-virus program on it and make sure you update it regularly. If you have an auto-update option included in your anti-virus program you should turn it on, that way if you forget to update your software you can still be protected from threats

44. 44 Precautions against Trojan Horses (3) Operating systems offer patches to protect their users from certain threats and viruses, including Trojan Horses. Software developers like Microsoft offer patches that in a sense “close the hole” that the Trojan horse or other virus would use to get through to your system. If you keep your system updated with these patches your computer is kept much safer. Avoid using peer-2-peer or P2P sharing networks like Kazaa, Limewire, Ares, or Gnutella because 1)those programs are generally unprotected from Trojan Horses 2)Trojan Horses are especially easy to spread through these programs Some of these programs do offer some virus protection but often they are not strong enough.

45. 45 Precautions against Trojan Horses (4) NEVER download blindly from people or sites which you aren’t 100% sure about. However, legal web sites may be comprised by attackers who may modify web pages to contain scripts to download malware. Even if the file comes form a friend, you still must be sure what the file is before opening it. (Ask your friend whether she/he sent the files to you.) Beware of hidden file extensions (Under Windows susie.jpg.exe is only shown as susie.jpg ) Never user features in your programs that automatically get or preview files (outlook, preview mode ). Never blindly type commands that others tell you to type, or go to the web site mentioned by strangers.

46. 46 Well-known Trojan Horses Back Orifice Back Orifice 2000 Beast Trojan NetBus SubSeven Downloader-EV Pest Trap flooder Tagasaurus Vundo trojan Gromozon Trojan

47. 47 Experiment Survey some Trojan horses to see what approaches are adopted by them to fool a user to execute them.

48. 48 List of Trojan Horses http://en.wikipedia.org/wiki/List_of_trojan_horses

49. 49 Spyware [Wikipedia]Wikipedia

50. 50 A Large Number of Toolbars, Some Added by Spyware, Overwhelm an IE SessionToolbars

51. 51 Definition of Spyware Spyware is computer software that is installed surreptitiously on a personal computer to monitor, intercept or take partial control over the user's interaction with the computer, without the user's informed consent. Spyware programs can secretly monitor the user's behavior and then send this information to a hacker over the Internet collect various types of personal information interfere with user control of the computer in other ways, such as installing additional software redirecting Web browser activity diverting advertising revenue to a third party.

52. 52 Types of Information Collected by Spyware Spyware can collect many different types of information about a user. More benign programs can attempt to track what types of websites a user visits and send this information to an advertisement agency. More malicious versions can try to record what a user types to try to intercept passwords or credit card numbers. Yet other versions simply launch pop-ups with advertisements.

53. 53 OSes Where Spyware Resides As of 2006, spyware has become one of the pre-eminent security threats to computer- systems running Microsoft Windows OSes. Some malware on the Linux and Mac OS X platforms has behavior similar to Windows spyware, but to date has not become anywhere near as widespread.

54. 54 Spyware Certification The Spyware-Free Certification program evaluates software to ensure that the program does not install or execute any forms of malicious code.Spyware-Free Certification program

55. 55 Typical Tactics Adopted by Spyware Delivery of unsolicited pop-up advertisements. Monitoring of Web-browsing activity for marketing purposes. Theft of personal information

56. 56 Adware The term adware frequently refers to any software which displays advertisements, whether or not it does so with the user's consent. Programs such as the Eudora mail client display advertisements as an alternative to shareware registration fees. These classify as "adware" in the sense of advertising-supported software, but not as spyware. Adware in this form does not operate surreptitiously or mislead the user, and provides the user with a specific service.

57. 57 Spyware and Pop-up Ads Spyware displays advertisements related to what it finds from spying on you, not the ones posted by advertisers. Claria Corporation's Gator Software and Exact Advertising's BargainBuddy provide examples of this sort of program. Visited Web sites frequently install Gator on client machines in a surreptitious manner, and it directs revenue to the installing site and to Claria by displaying advertisements to the user. The user experiences a large number of pop-up advertisements.

58. 58 Pop-up Ads Pop-up ads or popups are a form of online advertising on the World Wide Web. It works when certain web pages open a new web browser window to display advertisements. The pop-up window containing an advertisement is usually generated by JavaScript, but can be generated by other means as well.

59. 59 Pop-under Ads A variation on the pop-up window is the pop-under advertisement. This opens a new browser window, behind the active window. Pop-unders interrupt the user less, but are not seen until the desired windows are closed, making it more difficult for the user to determine which Web page opened them.

60. 60 Dozens of Pop-up Ads Cover a Desktop.

61. 61 Web Activity Monitor Other spyware behavior, such as reporting on websites the user visits, frequently accompany the displaying of advertisements. Monitoring web activity aims at building up a marketing profile on users in order to sell "targeted" advertisement impressions. The prevalence of spyware has cast suspicion upon other programs that track Web browsing, even for statistical or research purposes. Some observers describe the Alexa Toolbar, an Internet Explorer plug-in published by Amazon.com, as spyware (and some anti-spyware programs report it as such) although many users choose to install it.

62. 62 Identity Theft and Fraud Some spyware is closely associated with identity theft. Spyware may transmit the following information to attackers: chat sessions, user names, passwords, bank information, etc. Spyware has principally become associated with identity theft in that keyloggers are routinely packaged with spyware. John Bambenek, who researches information security, estimates that identity thieves have stolen over $24 billion US dollars of account information in the United States alone

63. 63 Routes of Infection

64. 64 Routes of Infection Spyware does not directly spread in the manner of a computer virus or worm: generally, an infected system does not attempt to transmit the infection to other computers. Instead, spyware gets on a system through deception of the user or through exploitation of software vulnerabilities.

65. 65 Masquerade One way of distributing spyware involves tricking users by manipulating security features designed to prevent unwanted installations. The Internet Explorer Web browser, by design, prevents websites from initiating an unwanted download. Instead, a user action (such as clicking on a link) must normally trigger a download. However, links can prove deceptive: For instance, a pop-up ad may appear like a standard Windows dialog box. The box contains a message such as "Would you like to optimise your Internet access?" with links which look like buttons reading Yes and No. No matter which "button" the user presses, a download starts, placing the spyware on the user's system.

66. 66 A Masquerade Example Malicious websites may attempt to install spyware on readers' computers. In this screenshot a website has triggered a pop-up that offers spyware in the guise of a security upgrade.

67. 67 Bundled with Shareware Spyware can also come bundled with shareware other downloadable software music CDs. The user downloads a program (for instance, a music program or a file-trading utility) and installs it, and the installer additionally installs the spyware. Although the desirable software itself may do no harm, the bundled spyware does. In some cases, spyware authors have paid shareware authors to bundle spyware with their software. In other cases, spyware authors have repackaged desirable free software with installers that add spyware.

68. 68 Bundled Shareware Example The BearShare file-trading program, "supported" by WhenU spyware. In order to install BearShare, users must agree to install "the SAVE! bundle" from WhenU. The installer provides only a tiny window in which to read the lengthy license agreement. Although the installer claims otherwise, the software transmits users' browsing activity to WhenU servers.

69. 69 Through Trojan Horse Classically, a Trojan horse, by definition, smuggles in something dangerous in the guise of something desirable. Some spyware programs get spread in just this manner. The distributor of spyware presents the program as a useful utility — for instance as a Web accelerator or as a helpful software agent. Users download and install the software without immediately suspecting that it could cause harm.

70. 70 Vulnerabilities in Web Browsers Some spyware authors infect a system by attacking security holes in the Web browser or in other software. When the user navigates to a Web page controlled by the spyware author, the page contains code which attacks the browser and forces the download and install of spyware. Common browser exploits target security vulnerabilities in Internet Explorer and in the Microsoft Java runtime.

71. 71 Notable Programs Distributed with Spyware Messenger Plus! (only if you agree to install their "sponsor" program) Bearshare Bonzi Buddy DAEMON Tools (only if you agree to install their "sponsor" program) DivX (except for the paid version, and the "standard" version without the encoder). DivX announced removal of GAIN software from version 5.2. Dope Wars ErrorGuard FlashGet (free version) Grokster Kazaa Morpheus RadLight WeatherBug EDonkey2000

72. 72 Worm

73. 73 Worms Attack running processes to spread themselves. Most frequently used attack approaches included buffer overflow attacks, format string attacks, integer overflow attacks, … and so on. Morris Worm,1988 Code Red, Slammer.

74. 74 Comparisons between Viruses, Trojan Horses, and Worms The way they behave How are they triggered? How do they spread? Need host programs?