HijackThis log tutorial |
| by Merijn | ||
| December 30, 2003 | ||
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On the forums of SpywareInfo, a lot of people new to browser hijacking post topics asking for help analyzing logs from HijackThis, because they don't understand what stuff is good and what is bad. Overview Each line in a HijackThis log starts with a section name. (For technical information on this, click 'Info' in the main window and scroll down. Highlight a line and click 'More info on this item'.)For practical information, click the section name you need help with:
R0, R1, R2, R3 - IE Start & Search page What it looks like:R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page=http://www.google.com/What to do: If you recognize the URL at the end as your homepage or search engine, it's OK. If you don't, check it and have HijackThis fix it. For the R3 items, always fix them unless it mentions a program you recognize, like Copernic. F0, F1, F2, F3- Autoloading programs from INI files What it looks like:F0 - system.ini: Shell=Explorer.exe Openme.exeWhat to do: The F0 items are always bad, so fix them. The F1 items are usually very old programs that are safe, so you should find some more info on the filename to see if it's good or bad. Pacman's Startup List can help with identifying an item. N1, N2, N3, N4 - Netscape/Mozilla Start & Search page What it looks like:N1 - Netscape 4: user_pref("browser.startup.homepage", "www.google.com"); (C:\Program Files\Netscape\Users\default\prefs.js)What to do: Usually the Netscape and Mozilla homepage and search page are safe. They rarely get hijacked only Lop.com has been known to do this. Should you see an URL you don't recognize as your homepage or search page, have HijackThis fix it. O1 - Hostsfile redirections What it looks like:O1 - Hosts: 216.177.73.139 auto.search.msn.comWhat to do: This hijack will redirect the address to the right to the IP address to the left. If the IP does not belong to the address, you will be redirected to a wrong site everytime you enter the address. You can always have HijackThis fix these, unless you knowingly put those lines in your Hosts file. The last item sometimes occurs on Windows 2000/XP with a Coolwebsearch infection. Always fix this item, or have CWShredder repair it automatically. O2 - Browser Helper Objects What it looks like:O2 - BHO: Yahoo! Companion BHO - {13F537F0-AF09-11d6-9029-0002B31F9E59} - C:\PROGRAM FILES\YAHOO!\COMPANION\YCOMP5_0_2_4.DLLWhat to do: If you don't directly recognize a Browser Helper Object's name, use TonyK's BHO List to find it by the class ID (CLSID, the number between curly brackets) and see if it's good or bad. In the BHO List, 'X' means spyware and 'L' means safe. O3 - IE toolbars What it looks like:O3 - Toolbar: &Yahoo! Companion - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\PROGRAM FILES\YAHOO!\COMPANION\YCOMP5_0_2_4.DLLWhat to do: If you don't directly recognize a toolbar's name, use TonyK's Toolbar List to find it by the class ID (CLSID, the number between curly brackets) and see if it's good or bad. In the Toolbar List, 'X' means spyware and 'L' means safe. If it's not on the list and the name seems a random string of characters and the file is in the 'Application Data' folder (like the last one in the examples above), it's probably Lop.com, and you definately should have HijackThis fix it. O4 - Autoloading programs from Registry or Startup group What it looks like:O4 - HKLM..Run: [ScanRegistry] C:\WINDOWS\scanregw.exe /autorunWhat to do: Use PacMan's Startup List to find the entry and see if it's good or bad. If the item shows a program sitting in a Startup group (like the last item above), HijackThis cannot fix the item if this program is still in memory. Use the Windows Task Manager (TASKMGR.EXE) to close the process prior to fixing. O5 - IE Options not visible in Control Panel What it looks like:O5 - control.ini: inetcpl.cpl=noWhat to do: Unless you or your system administrator have knowingly hidden the icon from Control Panel, have HijackThis fix it. O6 - IE Options access restricted by Administrator What it looks like:O6 - HKCU\ Software\Policies\Microsoft\Internet Explorer\Restrictions presentWhat to do: Unless you have the Spybot S&D option 'Lock homepage from changes' active, or your system administrator put this into place, have HijackThis fix this. O7 - Regedit access restricted by Administrator What it looks like:O7 - HKCU\Software\Microsoft\Windows ::CurrentVersion\Policies\System, DisableRegedit=1What to do: Always have HijackThis fix this, unless your system administrator has put this restriction into place. O8 - Extra items in IE right-click menu What it looks like:O8 - Extra context menu item: &Google Search - res://C:\WINDOWS\DOWNLOADED PROGRAM FILES\GOOGLETOOLBAR_EN_1.1.68-DELEON.DLL/cmsearch.htmlWhat to do: If you don't recognize the name of the item in the right-click menu in IE, have HijackThis fix it. O9 - Extra buttons on main IE toolbar, or extra items in IE 'Tools' menu What it looks like:O9 - Extra button: Messenger (HKLM)What to do: If you don't recognize the name of the button or menuitem, have HijackThis fix it. O10 - Winsock hijackers What it looks like:O10 - Hijacked Internet access by New.NetWhat to do: It's best to fix these using LSPFix from Cexx.org, or Spybot S&D from Kolla.de. Note that 'unknown' files in the LSP stack will not be fixed by HijackThis, for safety issues. O11 - Extra group in IE 'Advanced Options' window What it looks like:O11 - Options group: [CommonName] CommonNameWhat to do: The only hijacker as of now that adds its own options group to the IE Advanced Options window is CommonName. So you can always have HijackThis fix this. O12 - IE plugins What it looks like:O12 - Plugin for .spop: C:\Program Files\Internet Explorer\Plugins\NPDocBox.dllWhat to do: Most of the time these are safe. Only OnFlow adds a plugin here that you don't want (.ofb). O13 - IE DefaultPrefix hijack What it looks like:O13 - DefaultPrefix: http://www.pixpox.com/cgi-bin/click.pl?url=What to do: These are always bad. Have HijackThis fix them. O14 - 'Reset Web Settings' hijack What it looks like:O14 - IERESET.INF: START_PAGE_URL=http://www.searchalot.comWhat to do: If the URL is not the provider of your computer or your ISP, have HijackThis fix it. O15 - Unwanted site in Trusted Zone What it looks like:O15 - Trusted Zone: http://free.aol.com O15 - Trusted Zone: *.coolwebsearch.com O15 - Trusted Zone: *.msn.comWhat to do: Most of the time only AOL and Coolwebsearch silently add sites to the Trusted Zone. If you didn't add the listed domain to the Trusted Zone yourself, have HijackThis fix it. O16 - ActiveX Objects (aka Downloaded Program Files) What it looks like:O16 - DPF: Yahoo! Chat - http://us.chat1.yimg.com/us.yimg.com/i/chat/applet/c381/chat.cabWhat to do: If you don't recognize the name of the object, or the URL it was downloaded from, have HijackThis fix it. If the name or URL contains words like 'dialer', 'casino', 'free_plugin' etc, definitely fix it. Javacool's SpywareBlaster has a huge database of malicious ActiveX objects that can be used for looking up CLSIDs. (Right-click the list to use the Find function.) O17 - Lop.com domain hijacks What it looks like:O17 - HKLM\System\CCS\Services\VxD ::MSTCP: Domain = aoldsl.netWhat to do: If the domain is not from your ISP or company network, have HijackThis fix it. The same goes for the 'SearchList' entries. For the 'NameServer' (DNS servers) entries, Google for the IP or IPs and it will be easy to see if they are good or bad. O18 - Extra protocols and protocol hijackers What it looks like:O18 - Protocol: relatedlinks - {5AB65DD4-01FB-44D5-9537-3767AB80F790} - C:\PROGRA~1\COMMON~1\MSIETS\msielink.dllWhat to do: Only a few hijackers show up here. The known baddies are 'cn' (CommonName), 'ayb' (Lop.com) and 'relatedlinks' (Huntbar), you should have HijackThis fix those. Other things that show up are either not confirmed safe yet, or are hijacked (i.e. the CLSID has been changed) by spyware. In the last case, have HijackThis fix it. O19 - User style sheet hijack What it looks like:O19 - User style sheet: c:\WINDOWS\Java\my.cssWhat to do: In the case of a browser slowdown and frequent popups, have HijackThis fix this item if it shows up in the log. However, since only Coolwebsearch does this, it's better to use CWShredder to fix it. O20 - AppInit_DLLs Registry value autorun What it looks like:O20 - AppInit_DLLs Registry value autorunWhat to do: This Registry value located at HKEY_LOCAL_MACHINE\Software\Microsoft ::Windows NT\CurrentVersion\Windows loads a DLL into memory when the user logs in, after which it stays in memory until logoff. Very few legitimate programs use it (Norton CleanSweep uses APITRAP.DLL), most often it is used by trojans or agressive browser hijackers. In case of a 'hidden' DLL loading from this Registry value (only visible when using 'Edit Binary Data' option in Regedit) the dll name may be prefixed with a pipe '|' to make it visible in the log. O21 - ShellServiceObjectDelayLoad autorun What it looks like:O21 - SSODL - AUHOOK - {11566B38-955B-4549-930F-7B7482668782} - C:\WINDOWS\System\auhook.dll What to do: This is an undocumented autorun method, normally used by a few Windows system components. Items listed at HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\ShellServiceObjectDelayLoad are loaded by Explorer when Windows starts. HijackThis uses a whitelist of several very common SSODL items, so whenever an item is displayed in the log it is unknown and possibly malicious. Treat with extreme care. O22 - SharedTaskScheduler What it looks like:O22 - SharedTaskScheduler: (no name) - {3F143C3A-1457-6CCA-03A7-7AA23B61E40F} - c:\windows\system32\mtwirl32.dll What to do: This is an undocumented autorun for Windows NT/2000/XP only, which is used very rarely. So far only CWS.Smartfinder uses it. Treat with care. O23 - NT Services What it looks like:O23 - Service: Kerio Personal Firewall (PersFw) - Kerio Technologies - C:\Program Files\Kerio\Personal Firewall\persfw.exe What to do: This is the listing of non-Microsoft services. The list should be the same as the one you see in the Msconfig utility of Windows XP. Several trojan hijackers use a homemade service in adittion to other startups to reinstall themselves. The full name is usually important-sounding, like 'Network Security Service', 'Workstation Logon Service' or 'Remote Procedure Call Helper', but the internal name (between brackets) is a string of garbage, like 'O? ’ŽrtñåȲ$Ó'. The second part of the line is the owner of the file at the end, as seen in the file's properties. Note that fixing an O23 item will only stop the service and disable it. The service needs to be deleted from the Registry manually or with another tool. In HijackThis 1.99.1 or higher, the button 'Delete NT Service' in the Misc Tools section can be used for this.
Special thanks to Merijn, the creator of HijackThis, for granting us permission to reprint his tutorial on this incredibly useful program. The original tutorial can be found here. HijackThis can be downloaded here. |
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