Archive for May, 2016

Crash Dump Analysis Patterns (Part 241)

Sunday, May 29th, 2016

Most Execution Residue traces in memory dumps are not explicitly temporal (see Special and General Trace and Log Analysis) but may be ordered by some space coordinate, such as memory addresses or page frame numbers. Furthermore, virtual space can be further subdivided into places such as modules and physical space may be restructured into places such as processes. Simple space trace of some data value can be constructed using Value References analysis pattern. These and higher structural space trace constructs can be named as a general Place Trace analysis pattern illustrated in this diagram:

Memory attributes, such as page protection, or derived attributes from memory contents can also be considered as Place Trace data. Sometimes, time ordering can be reconstructed by looking at time information for place containers, for example, elapsed process time or ordering in the process list, or thread order and times for stack region thread owners.

- Dmitry Vostokov @ + -

Crash Dump Analysis Patterns (Part 240)

Sunday, May 29th, 2016

Windows processes may contain Execution Residue such as ASCII window class names in mapped memory regions pointing to other running processes (perhaps as a result of Hooksware). For example, calc.exe process memory dump saved on my Windows 10 notebook “knows” about Visio and WinDbg windows that were opened at that time:

00000015`42c6bdd0 56 49 53 49 4f 41 00 00-00 00 00 00 00 00 00 00 VISIOA.............

0:000> s-a 0 L?FFFFFFFFFFFFFFFF "WinDbg"
00000015`42d19720 57 69 6e 44 62 67 46 72-61 6d 65 43 6c 61 73 73 WinDbgFrameClass

This may be useful for some troubleshooting scenarios, for example, pointing to processes which are known for their problematic behavior or Special Processes. Of course, we assume that those windows or classes were genuine, not faked. We call this analysis pattern Window Hint similar to Environment Hint and Module Hint analysis patterns.

Going deeper, we can dump strings from the whole region limiting the output to the strings with length more than 5:

0:000> !address 00000015`42d19720

Usage:                  <unknown>
Base Address:           00000015`42b20000
End Address:            00000015`42d3a000

Region Size:            00000000`0021a000 (   2.102 MB)
State:                  00001000          MEM_COMMIT
Protect:                00000002          PAGE_READONLY
Type:                   00040000          MEM_MAPPED
Allocation Base:        00000015`42b20000
Allocation Protect:     00000002          PAGE_READONLY

Content source: 1 (target), length: 208e0

0:000> s-[l5]sa 00000015`42b20000 00000015`42d3a000
00000015`42b20a60  “#32769″
00000015`42b20cc0  “Message”
00000015`42b20f40  “#32774″
00000015`42b21060  “#32772″
00000015`42b21510  “Ghost”
00000015`42b215e0  “LivePreview”
00000015`42b216f0  “UserAdapterWindowClass”
00000015`42b21ce0  “MSCTFIME Composition”
00000015`42b222a0  “#32772″
00000015`42b22390  “#32772″
00000015`42b22460  “RichEdit20W”
00000015`42b22530  “RichEdit20A”
00000015`42b22600  “ToolbarWindow32″
00000015`42b226e0  “tooltips_class32″
00000015`42b227c0  “msctls_statusbar32″
00000015`42b228a0  “SysListView32″
00000015`42b22980  “SysHeader32″
00000015`42b22a50  “SysTabControl32″
00000015`42b22b30  “SysTreeView32″
00000015`42b22c10  “msctls_trackbar32″
00000015`42b22cf0  “msctls_updown32″
00000015`42b22dd0  “msctls_progress32″
00000015`42b22eb0  “msctls_hotkey32″
00000015`42b22f8f  “‘SysAnimate32″
00000015`42b230f0  “SysIPAddress32″
00000015`42b231d0  “ReBarWindow32″
00000015`42b232b0  “ComboBoxEx32″
00000015`42b23390  “SysMonthCal32″
00000015`42b23470  “SysDateTimePick32″
00000015`42b23550  “DropDown”
00000015`42b23620  “SysLink”
00000015`42b236f0  “SysPager”
00000015`42b23960  “msctls_netaddress”


00000015`42d175e0  "OutlookFbThreadWnd"
00000015`42d19720  "WinDbgFrameClass"
00000015`42d19750  "DockClass"
00000015`42d19770  "GhostClass"
00000015`42d19a30  "ATL:00007FF60D792730"
00000015`42d1a0f0  "MSCTFIME Composition"
00000015`42d1a4af  "%OleMainThreadWndClass"
00000015`42d1be10  "CicMarshalWndClass"
00000015`42d1c0e0  "VSyncHelper-00000040EC4CA5F0-1f8"
00000015`42d1c100  "8855daf"
00000015`42d1c190  "URL Moniker Notification Window"
00000015`42d1c390  "UserAdapterWindowClass"
00000015`42d1d080  "@>zG#"
00000015`42d1dcaf  "!VSyncHelper-00000040D60C5850-1e"
00000015`42d1dccf  "ef0477df"
00000015`42d20d50  "VSyncHelper-00000040F39C5650-1f0"
00000015`42d20d70  "313c5a0"
00000015`42d250d0  "#32770"
00000015`42d250f0  "URL Moniker Notification Window"
00000015`42d29270  "VSyncHelper-00000079321C32E0-1f2"
00000015`42d29290  "fb11f8c"
00000015`42d2a1d0  "MSCTFIME Composition"
00000015`42d2a480  "CicMarshalWndClass"
00000015`42d2ac80  "MSCTFIME Composition"
00000015`42d2b8d0  "ShockwaveFlashFullScreen"
00000015`42d2bbb8  "P?U!\"
00000015`42d2c690  "Xaml_WindowedPopupClass"
00000015`42d30a10  "ShockwaveFlashFullScreen"
00000015`42d30b50  "MSCTFIME UI"
00000015`42d30b90  "WinBaseClass"
00000015`42d3441f  "!Alternate Owner"
00000015`42d34460  "ShockwaveFlashFullScreen"
00000015`42d344a0  "ATL:00007FF60D792530"
00000015`42d34a50  "SysAnimate32"
00000015`42d34a7f  "'ComboBoxEx32"
00000015`42d34ed0  "tooltips_class32"
00000015`42d34f00  "msctls_statusbar32"
00000015`42d35e70  "RawInputClass"
00000015`42d36a10  "SysTabControl32"
00000015`42d38650  "CicMarshalWndClass"
00000015`42d38eb0  "#32772"
00000015`42d3951f  "!VSyncHelper-000000C9DA06CD10-1f"
00000015`42d3953f  "110e8d16"

- Dmitry Vostokov @ + -

Crash Dump Analysis Patterns (Part 239)

Monday, May 2nd, 2016

We found out that in Windows 10 (at least on our working system) Notepad is no longer a single threaded application even without opening any common dialogs (like in Evental Dumps analysis pattern example). It has at least 3 additional threads (and other modeling applications we use for our training also have additional threads):

0:000> ~*k

0 Id: 3a64.3b38 Suspend: 1 Teb: 00007ff6`a914d000 Unfrozen
# Child-SP RetAddr Call Site
00 000000e5`6298f938 00007ffa`e57cf8e5 USER32!NtUserGetMessage+0xa
01 000000e5`6298f940 00007ff6`a9603470 USER32!GetMessageW+0x25
02 000000e5`6298f970 00007ff6`a96141f5 notepad!WinMain+0x178
03 000000e5`6298f9f0 00007ffa`e3b42d92 notepad!WinMainCRTStartup+0x1c5
04 000000e5`6298fab0 00007ffa`e5bc9f64 KERNEL32!BaseThreadInitThunk+0x22
05 000000e5`6298fae0 00000000`00000000 ntdll!RtlUserThreadStart+0x34

1 Id: 3a64.38b0 Suspend: 1 Teb: 00007ff6`a914b000 Unfrozen
# Child-SP RetAddr Call Site
00 000000e5`62bffa58 00007ffa`e5bf93a5 ntdll!NtWaitForWorkViaWorkerFactory+0xa
01 000000e5`62bffa60 00007ffa`e3b42d92 ntdll!TppWorkerThread+0x295
02 000000e5`62bffe60 00007ffa`e5bc9f64 KERNEL32!BaseThreadInitThunk+0x22
03 000000e5`62bffe90 00000000`00000000 ntdll!RtlUserThreadStart+0x34

2 Id: 3a64.3940 Suspend: 1 Teb: 00007ff6`a9149000 Unfrozen
# Child-SP RetAddr Call Site
00 000000e5`62c7f718 00007ffa`e5bf93a5 ntdll!NtWaitForWorkViaWorkerFactory+0xa
01 000000e5`62c7f720 00007ffa`e3b42d92 ntdll!TppWorkerThread+0x295
02 000000e5`62c7fb20 00007ffa`e5bc9f64 KERNEL32!BaseThreadInitThunk+0x22
03 000000e5`62c7fb50 00000000`00000000 ntdll!RtlUserThreadStart+0x34

3 Id: 3a64.1030 Suspend: 1 Teb: 00007ff6`a9147000 Unfrozen
# Child-SP RetAddr Call Site
00 000000e5`62d1f878 00007ffa`e5bf93a5 ntdll!NtWaitForWorkViaWorkerFactory+0xa
01 000000e5`62d1f880 00007ffa`e3b42d92 ntdll!TppWorkerThread+0x295
02 000000e5`62d1fc80 00007ffa`e5bc9f64 KERNEL32!BaseThreadInitThunk+0x22
03 000000e5`62d1fcb0 00000000`00000000 ntdll!RtlUserThreadStart+0x34

This gave us an idea for the analysis pattern we call Not My Thread since additional threads can be started by any other process DLLs, for example, by Hooksware. However, we need to distinguish between unexpectedly added threads, threads with Special Stack Traces and Special Threads, for example, from .NET support.

- Dmitry Vostokov @ + -