4720830 RT_ICON (3) -\n4703093 RT_GROUP_ICON (14) -\n3445748 RT_VERSION (16) -\n2574034 RT_MANIFEST (24) -\n2291058 RT_DIALOG (5) -\n2022739 RT_STRING (6) -\n1564623 RT_RCDATA (10) -\n1193659 RT_BITMAP (2) -\n1159726 'DVCLAL' -\n1050941 'PACKAGEINFO' -\n 931572 'MAINICON' -\n 903265 RT_CURSOR (1) -\n 884868 RT_GROUP_CURSOR (12) -\n 557473 'BBABORT' -\n 551898 'BBALL' -\n 551836 'BBOK' -\n 551785 'BBNO' -\n 551023 'BBRETRY' -\n 542886 'BBIGNORE' -\n 542836 'BBHELP' -\n 542834 'BBCLOSE' -\n 542593 'BBYES' -\n 541708 'BBCANCEL' -\n 498816 'PREVIEWGLYPH' -\n 497272 'DLGTEMPLATE' -\n 358081 RT_MENU (4) -\n 199615 'TFORM1' -\n 174781 RT_ACCELERATOR (9) -\n<\/code><\/pre>\n\n\n\nThese with a RT_prefix are standard resource types defined<\/a> by Microsoft, and the ones in apostrophes are strings that ‘tag’ (or ‘name’) the resources according to developer’s wishes… <\/p>\n\n\n\nGiven a number of these ‘named’ ones used repeatedly (as shown by the list above) you can guess that they are somehow ‘known’, or a part of some ‘standard’ — and yup, these are primarily from Borland\/Delphi\/Embarcadero family of executables that include standard GUI elements from this platform. All ‘BB*’ and ‘T*’ come from this environment. Additionally ‘PACKAGEINFO’ is a resource I covered a little bit in the past<\/a> – it lists all the packages the executable uses (a good IOC except no one writes malware in Delphi anymore).<\/p>\n\n\n\nSurprisingly, modern PE Viewers and Editors do not parse PE resources very well. They only show the most popular resource types, because the others are often … undocumented. I really don’t like to look at resources in hex view. We can do better.<\/p>\n\n\n\n
Let’s start with these that are ‘kinda documented’. <\/p>\n\n\n\n
For instance, Resource Hacker can handle some Delphi resources (e.g. forms) pretty well:<\/p>\n\n\n\n![\"\"](\"https:\/\/www.hexacorn.com\/blog\/wp-content\/uploads\/2020\/04\/res_1.png\")
<\/a><\/figure>\n\n\n\nA popular ‘Typelib’ resource:<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.hexacorn.com\/blog\/wp-content\/uploads\/2020\/04\/res_2.png\")
<\/a><\/figure><\/div>\n\n\n\ncan be viewed with OleView:<\/p>\n\n\n\n
![\"\"](\"https:\/\/www.hexacorn.com\/blog\/wp-content\/uploads\/2020\/04\/res_3.png\")
<\/a><\/figure><\/div>\n\n\n\nThe ‘Registry’ is typically an embedded ‘.reg’ file.<\/p>\n\n\n\n
A ‘FOMB’ is a binary MOF that was described in this post<\/a> by FireEye and can be decoded using bmfdec<\/a>.<\/p>\n\n\n\nWhat about the others?<\/p>\n\n\n\n
And this is where it gets really difficult…<\/p>\n\n\n\n
Looking at resources embedded in Windows 10 exe, dll, ocx files one can very quickly build a list of more or less enigmatically-looking resource names:<\/p>\n\n\n\n
- ACCELERATOR<\/li>
- ANICURSOR<\/li>
- AVI<\/li>
- BINARY<\/li>
- BITMAP<\/li>
- BITMAP4<\/li>
- BRANDING_METADATA_RES<\/li>
- BRANDING_REQUIRED_RESOURCEID_MAP<\/li>
- CERT<\/li>
- CODEPAGES<\/li>
- CODEPAGESEXT<\/li>
- CURSOR<\/li>
- DATA_FILE<\/li>
- DATAFILERESOURCE<\/li>
- DGML<\/li>
- DIALOG<\/li>
- DUI<\/li>
- EDPAUTOPROTECTIONALLOWEDAPPINFOID<\/li>
- EDPENLIGHTENEDAPPINFOID<\/li>
- EDPPERMISSIVEAPPINFOID<\/li>
- EMBEDDEDDATA<\/li>
- FILES<\/li>
- FLEX_TABLE<\/li>
- FLEXDL<\/li>
- FONT<\/li>
- FONTDIR<\/li>
- FONTFALLBACK<\/li>
- GIF<\/li>
- GROUP_CURSOR<\/li>
- GROUP_ICON<\/li>
- HTML<\/li>
- HWB<\/li>
- HWXLANGID<\/li>
- IBC<\/li>
- ICON<\/li>
- IMAGE<\/li>
- JPEG<\/li>
- JS<\/li>
- JSON<\/li>
- JSON_RESPONSE<\/li>
- MANIFEST<\/li>
- MENU<\/li>
- MESSAGETABLE<\/li>
- MOFDATA<\/li>
- MSTESTROOT<\/li>
- MUI<\/li>
- PNG<\/li>
- PNGFILE<\/li>
- PRELOAD<\/li>
- PRXFILE<\/li>
- RCDATA<\/li>
- REGINST<\/li>
- REGISTRY<\/li>
- RGSLIST<\/li>
- SCHEMA<\/li>
- SIAMDB<\/li>
- SKDFILE<\/li>
- SRGRAMMAR<\/li>
- STYLE_XML<\/li>
- TESTROOT<\/li>
- TEXT<\/li>
- TEXTINCLUDE<\/li>
- TUNINGSPACE<\/li>
- TYPELIB<\/li>
- UIFILE<\/li>
- VR_ETW_MANIFEST<\/li>
- VR_ETW_RESOURCE<\/li>
- VSGEXP<\/li>
- WAVE<\/li>
- WEVT_TEMPLATE<\/li>
- XML<\/li>
- XML_FILE<\/li>
- XML_SCHEMA<\/li>
- XMLFILE<\/li>
- XSD<\/li>
- XSDFILE<\/li>
- XSLFILE<\/li><\/ul>\n\n\n\n
Yup. Some are easy to handle (just by looking at their name e.g. AVI, BITMAP, XML), but… this is just Windows 10. <\/p>\n\n\n\n
Time will tell if we will ever see a PE editor\/viewer that can handle all of, or at least most of these well.<\/p>\n\n\n\n
In the meantime…<\/p>\n\n\n\n
Resources is something you may want to look at more closely. Starting today.<\/p>\n\n\n\n
Why?<\/p>\n\n\n\n
Because of this guy:<\/p>\n\n\n\n![\"\"](\"https:\/\/www.hexacorn.com\/blog\/wp-content\/uploads\/2020\/04\/norton.png\")
<\/figure>\n\n\n\nI got it from resources of Norton SecureWorks circa 2002-2003. Do you even remember this software existed?<\/p>\n\n\n\n
One of cool side-effects of poking around in many resources is coming across weird, unusual strings, texts, images, movies, you name it. You will find developer pictures that were not meant for general public, ‘tagging’ images with names of developers of project managers, jokes, and whatever else. Yes, there is cheezy, there is porn, there are obscenities, there are also Easter Eggs. <\/p>\n\n\n\n
If you want to start building your own collection, it couldn’t be easier…<\/p>\n\n\n\n
You can simply use:<\/p>\n\n\n\n
- 7z l <filename> .rsrc
- to list all the resources of a <filename> <\/li><\/ul><\/li>
- 7z x <filename> .rsrc’
- to extract them.<\/li><\/ul><\/li><\/ul>\n\n\n\n
And then start data crunching:<\/p>\n\n\n\n
- Icons are interesting, especially if re-used for malicious purposes (e.g. Adobe, Microsoft) –> there are existing yara sigs for these!<\/li>
- Manifest may include references to other executables\/DLLs loaded<\/li>
- Manifest may also include references to rights required for running the executable (e.g. look for level=”requireAdministrator”)<\/li>
- Language information may be helpful with attribution (beware of false flags)<\/li>
- Version Information lists lots of interesting information that can be co-related with the information extracted from certificates \/ signatures, if present<\/li>
- Delphi resources are fairly well documented and can be extracted, especially the aforementioned package names — can help to at least cluster samples as per the modules used (may sometimes highlight similar families, plus good for yara sigs)<\/li>
- Everything else should be extracted and checked against typical file types\/magic:
- BMP<\/li>
- PNG<\/li>
- GIF<\/li>
- JPG<\/li>
- AVI<\/li>
- Wav<\/li>
- Rtf<\/li>
- Ico<\/li>
- Cur<\/li>
- PE files<\/li>
- LE files (older version of MZ executables)<\/li>
- MZ files (yup, plain DOS)<\/li>
- UTF8\/Unicode BOMs<\/li>
- Office files<\/li>
- etc.<\/li><\/ul><\/li><\/ul>\n\n\n\n
Resources are a very important metadata source for analysts. If you are lucky you may not only get the visuals, but also timestamps (e.g. in Delphi executables<\/a>).<\/p>\n\n\n\nBe err… resourceful.<\/p>\n","protected":false},"excerpt":{"rendered":"
PE Resources are like an unwanted child of malware analysis and reverse engineering. Almost no one talks about them and… this post is going to… make it worse ;). Let’s take a large number of ‘bad’ samples, export their resource … Continue reading