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Trojans, Backdoors, and Sniffers

Trojans, Backdoors, and Sniffers. BAI514 – Security I. Trojans, Backdoors, and Sniffers. Trojans have been around since ancient times. Trojans are malicious pieces of software used to install hacking software on a target system.

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Trojans, Backdoors, and Sniffers

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  1. Trojans, Backdoors, and Sniffers BAI514 – Security I

  2. Trojans, Backdoors, and Sniffers • Trojans have been around since ancient times. • Trojans are malicious pieces of software used to install hacking software on a target system. • Trojans and their counterparts (backdoors and sniffers) are important pieces of the hacker’s toolkit

  3. Trojans and Backdoors • A trojan is a program that performs functions unwanted by the target. • Three accepted definitions • An unauthorized program contained within a legitimate program that performs functions unknown and unwanted by the user • A legitimate program that has been altered by the placement of unauthorized code within it and that performs functions unknown and unwanted by the user

  4. Trojans and Backdoors • Three accepted definitions (cont.) • Any program that appears to perform a desirable and necessary function but that, because of hidden and unauthorized code, performs functions unknown and unwanted by the user

  5. Trojans and Backdoors • A backdoor in a computer system secures remote access to the system for an attacker and allows the attacker to bypass normal authentication

  6. Trojans and Backdoors • Trojan types • Remote Access Trojan (RAT) • Keystroke logger or password sending trojan • Software detection killers • Purely destructive or service denying trojans • FTP trojans

  7. Trojans and Backdoors • Remote Access Trojans (RATs) • A program that surreptitiously allows access to a computer’s resources via a network connection • Generally consist of two parts • Client • Server – must be installed on the victim machine • Once installed, typically opens a port for communication and waits for the client to connect

  8. Trojans and Backdoors • Remote Access Trojans (RATs) (cont.) • Common Remote Access Port Numbers • Back Orifice 31337 UDP • BO2K 54320/54321 TCP/UDP • Beast 6666 TCP • Citrix ICA 1494 TCP/UDP • Donald Dick 23476/23477 TCP • Masters Paradise 40421-40426 TCP • Netmeeting R/C 49608/49609 TCP • NetBus 12345 TCP

  9. Trojans and Backdoors • Remote Access Trojans (RATs) (cont.) • Common Remote Access Port Numbers (cont.) • Netcat Various TCP • PCAnywhere 5631/5632/65301 TCP • Reachout 43188 TCP • Remotely anywhere 2000/2001 TCP • Remote 135-139 TCP/UDP • Timbuktu 407 TCP/UDP • VNC 5800/5801 TCP/UDP

  10. Trojans and Backdoors • Trojan Attack Vectors • Trojans employ attack vectors to install its payload on the target • Email and attachments • Deception and social engineering • Web bugs and driveby downloads • NetBIOS remote plants • Physical access • Attacks that exploit Windows and IE vulnerabilities • Web pages that install spyware and adware • Instant messaging and IRC • P2P networks

  11. Trojans and Backdoors • Trojan Attack Vectors (cont.) • Example: “Sepuc” • Delivered by email • Victims have no idea they’re being spied on • Email has no subject line and no visible text in the body • When opened, hidden code attempts to exploit a vulnerability in IE to force a download from a remote machine

  12. Trojans and Backdoors • Wrappers • A program used to combine two or more executables into a single packaged program. • The wrapper attaches a harmless executable, like a game, to a trojan’s payload • When run, the game is launched as expected, but the trojan is also launched, unknown to the user

  13. Trojans and Backdoors • Wrappers (cont.) • ELiTeWrap • Advanced executable wrapper for Windows • Can be used for archiving or secretly installing and running programs • Silk Rope • Easy to use GUI • Binds BO installer with the attackers program of choice

  14. Trojans and Backdoors • Wrappers (cont.) • Other wrappers • Saran Wrap • PE Bundle • Teflon Oil Patch (TOVB4) • AFX File Lace • Exe2vbs

  15. Trojans and Backdoors • Covert Communication • Utilize covert channels • A way of transmitting data by using a path differently from its original intention.

  16. Trojans and Backdoors • Covert Communication (cont.) • Covert storage channel • Conveys information by changing a system’s stored data • E.g. Changing the characteristics of a file • Covert timing channel • A covert channel in which one process signals information to another by modulating its own use of system resources in such a way that this manipulation affects the real response time observed by a second process

  17. Trojans and Backdoors • Covert Communication (cont.) • Covert communication tools • Rely on a technique called tunneling • Allows one protocol to be carried over another protocol • E.g. Loki – provides shell access over ICMP

  18. Trojans and Backdoors • Port Redirection • Listening on preconfigured port then redirecting all packets to a secondary destination • Some tools used for port redirection • Netcat • Reverse telnet • Datapipe • Fpipe • Rinetd

  19. Trojans and Backdoors • Port Redirection (cont.) • NetCat • Port redirection tool for both Unix and Windows • Uses either TCP or UDP • Datapipe • Unix redirection tool • Must be run on both ends of the attack • Fpipe • TCP port forwarder and redirector • Creates a TCP stream with a source port of your choice • Rinetd • Redirects TCP connections from one IP and port to another

  20. Trojans and Backdoors • Trojan tools and creation kits • Tini • Very small trojan backdoor (3KB) • Programmed in assembly language • Only listens on port 7777 • Runs a command prompt when someone attaches to this port • QAZ • Companion virus that can spread over a network • Has a backdoor using port 7597 to allow remote control • Renames the notepad program to note.exe

  21. Trojans and Backdoors • Trojan tools and creation kits (cont.) • Donald Dick • Remote access tool • Uses a client-server architecture • Uses TCP or SPX • Default ports are 23476 or 23477

  22. Trojans and Backdoors • Trojan tools and creation kits (cont.) • NetBus • Remote access tool • Created in 1998, translated to Swedish means “NetPrank” • Client-server architecture • Server has names like Patch.exe or SysEdit.exe • Uses ports 12345 or 12346

  23. Trojans and Backdoors • Trojan tools and creation kits (cont.) • Back Orifice 2000 • Spawned many imitators • Once installed on system, gives attacker complete control of the system • Has stealth capabilities • Will not show up in task list • Server is only 100KB • Client is only 500KB

  24. Trojans and Backdoors • Trojan tools and creation kits (cont.) • Back Orifice 2000 (cont.) • Plug-ins available • BOPeep – complete remote control snap-in • Encryption – encrypts all traffic between client and server • BOSOCK32 – allows use of ICMP rather than TCP • STCPIO – encrypts traffic between client and server

  25. Trojans and Backdoors • Trojan tools and creation kits (cont.) • SubSeven • Backdoor to allow full access to the system • Senna Spy • Trojan code generator • Hard Disk Killer • Can permanently destroy all data on any given DOS or Windows HD • FireKiller 2000 • Will kill any virus protection software • Disables personal firewalls • Beast • Very powerful RAT

  26. Trojans and Backdoors • Anti-Trojan Software and Countermeasures • Awareness works best! • Educate users • Develop effective policies • Cleaner (www.moosoft.com) can identify and remove 1000 types of backdoors and trojans • Windows File Protection (WFP) • Protects files installed by Windows setup • Generates hashes of all system files for comparison

  27. Trojans and Backdoors • Anti-Trojan Software and Countermeasures (cont.) • Tripwire • Automatically creates hashes of all key system files or any files you choose • Creates a baseline of the system • Periodically scans and compares baseline hashes for changes • Fport • Identifies unknown open ports and their associated applications

  28. Trojans and Backdoors • Anti-Trojan Software and Countermeasures (cont.) • TCPView • GUI showing all TCP and UDP endpoints • Process Viewer • GUI process viewer • Displays detailed information about processes running under Windows • Inzider • Tracks processes and ports • Not stable

  29. Sniffers • Sniffing is the process of gathering traffic from a network by capturing data as it passes and storing it to analyze later • A sniffer is a piece of software that captures the traffic flowing into and out of a computer attached to a network.

  30. Sniffers • Commonly used to gather login credentials • Attacks can include • Man-in-the-middle attacks • Session hijacking • Attacks commonly performed as a result of MAC flooding and ARP spoofing

  31. Sniffers • Sniffing exploits • Passive • Requires the introduction of a hub or network tap • Only packets passing through the hub or tap are captured • Active involved routing the traffic through the attacker’s computer • Two methods of active sniffing • ARP spoofing • MAC flooding

  32. Sniffers • ARP Spoofing (ARP poisoning) • Attacker configures IP forwarding on their computer • Attacker sends a fake ARP response to remap the default router’s IP to the attacker’s IP • Victim sends traffic destined for the outside world based on a poisoned ARP table entry • Victim’s redirected packets are forwarded through the switch to the attacker • Attacker sniffs the traffic • Victim’s packets are forwarded from the attacker’s computer to the actual gateway

  33. Sniffers • MAC Flooding • The act of attempting to overload the switch’s Content Addressable Memory (CAM) table • If the CAM table becomes full of entries, switches often fail open • All frames start flooding out all ports of the switch • MAC flooding may draw attention • Overall performance decreases

  34. Sniffers • DNS Spoofing or Poisoning • Occurs when a DNS entry points to another IP instead of the legitimate IP address • Also known as DNS cache poisoning • Process of distributing incorrect IP address information for a specific host with the intent to divert traffic from its true destination

  35. Sniffers • Sniffing Tools • Snort • Very powerful IDS • General purpose sniffer • Dsniff • Collection of tools for network auditing and penetration testing • Wireshark • Free network protocol anlyzer • Powerful

  36. Sniffers • Mac Flooding Tools • Etherflood • Floods a switched network with Ethernet frames containing random hardware addresses • SMAC 2.0 MAC Address Changer • Allows users to change MAC addresses for almost any NIC on Windows Vista, XP, 2003, and 2000 • Macof • Floods the local network with random MAC addresses

  37. Sniffers • ARP Poisoning Tools • Ettercap • Suite designed to facilitate man-in-the-middle attacks on a LAN • Features include sniffing and real-time content filtering, among others… • Cain • Multipurpose tool • Can perform ARP spoofing

  38. FIN

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