210 likes | 301 Views
AN INSIDE LOOK AT BOTNETS. Barford , Paul and Yegneswaran Advances in Information Security, Springer, 2006 Kishore Padma Raju. INTRODUCTION. Attacks for financial gain Proactive methods Understanding of malicious software readily available 4 IRC botnet codebases along 7 dimensions.
E N D
AN INSIDE LOOK AT BOTNETS Barford, Paul and Yegneswaran Advances in Information Security, Springer, 2006 KishorePadmaRaju
INTRODUCTION • Attacks for financial gain • Proactive methods • Understanding of malicious software readily available • 4 IRC botnet codebases along 7 dimensions
ARCHITECTURE • AGOBOT (Phatbot) • Found in october 2002 • Sophisticated and best written source code • 20,000 lines of c/c++ • High level components • IRC based command and control mechanism • Large collection of target exploits • DOS attacks • Harvest the local host
SDBOT • October 2002 • Simple code in C, 2000 lines • IRC based command and control system • Easy to extend and so many patches available(DOS attacks, information harvesting routines) • Motivation for patch dissemination is diffusion of accountability
SPYBOT • 3000 lines of C code • April 2003 • Evolved from SDBOT • No diffusion accountability • Includes scanning capability and launching flooding attacks • Efficient
GTBOT(global threat)(Aristotles) • Based on functions of mIRC(writes event handlers for remote nodes) • Capabilities are • Port scanning • DOS attacks • Stored in file mirc.ini • Remote execution • BNC(proxy system) , psexec.exe • Implications
BOTNET CONTROL MECHANISMS • Communication • Command language and control protocols • Based onIRC • Commands • Deny service • spam • Phish
Agobot • Command language contain Standad IRC and specific commands of this bot • Bot commands, perform specific function • Bot.open • Cvar.set • Ddos_max_threads
Sdbot NICK_USER PING 001/005 PONG 001/005 JOIN USERHOST NICK PREVMSG/ NOTICE/ TOPIC 302 EST KICK 353 PART/QUIT REJOIN RESET ACTION
SPYBOT • Command language simple • Commands are login, passwords, disconnect, reconnect, uninstall, spy, loadclones,killclones • GTBOT • Simplest • Varies across versions • Commands are !ver, !scan, !portscan, !clone.*,!update • IMPLICATIONS • Now simple • Future, encrypted communication • Finger printing methods
HOST CONTROL MECHANISMS • Manipulate victim host • AGOBOT • Commands to harvest sensitive information(harvest.cdkeys, harvest.emails, registry, windowskeys) • List and kill processes(pctrl.list, kill, killpid) • Add or delete autostart entries(inst.asadd, asdel) • SDBOT • Remote execution commands and gather local information • Patches • Host control commands (download, killthread, update)
SPYBOT • Control commands for file manipulation, key logging, remote command execution • Commands are delete, execute, makedir, startkeylogger, stopkilllogger, reboot, update. • GTBOT • Gathering local system information • Run or delete local files • IMPLICATIONS • Underscore the need to patch • Stronger protection boundaries • Gathering sensitive information
PROPAGATION MECHANISMS • Search for new host systems • Horizontal and vertical scan • AGOBOT • IP address within network ranges • Scan.addnetrange, scan.delnetrange, scan.enable • SDBOT • Same as agobot • NETBIOS scanner • Starting and end IP adresses
SPYBOT • Command interface • Command Scan <startipaddress> <port> <delay><spreaders><logfilename> • Example Scan 127.0.0.1 17300 1 netbios portscan.txt • GTBOT • Horizontal and vertical scanning • IMPLICATIONS • Simple scanning methods • Source code examination
EXPLOITS AND ATTACK MECHANISMS • Attack known vulnerabilities on target systems • AGOBOT • Broadening set of exploits • Generic DDOS module • Enables seven types of service attacks • Ddos.udpflood, synflood, httpflood, phatsyn, phaticmp,Phatwonk, targa3, stop. • SDBOT • UDP and ICMP packets, flooding attacks • udp <host> <#pkts> <pktsz><delay><port> and ping <host> <#pkts> <pktsz><timeout>
SPYBOT AND GTBOT • Same as sdbot • IMPLICATIONS • Multiple exploits
MALWARE DELIVERY MECHANISMS • GT/SD/SPY bots deliver exploit and encoded malware in single package • Agobot • Exploit vulnerability and open a shell on remote host • Encoded binary is then sent using HTTP or FTP. IMPLICATIONS
OBFUSCATION MECHANISMS • Hide the details • Polymorphism • AGOBOT • POLY_TYPE_XOR • POLY_TYPE_SWAP • POLY_TYPE_ROR • POLY_TYPE_ROL • IMPLICATIONS
CONCLUSIONS • Expanded the knowledge base for security research • Lethal classes of internet threats • Functional components of botnets
WEAKNESSES • Study only IRC • No Preventive mechanisms • No dynamic profiling of botnet executables • Insufficient analysis
IMPROVEMENTS • Dynamic profiling can be executed using some tools • Botnet monitoring mechanism can be explained • Analysis for peer to peer infrastructure