find Memory leak issue in .net Application Using Windbg

Question

Over the past few months, we've found issues in our application. The application works fine, but 1 or 2 times in a month the memory usage of the process increases to 30G in 15 minutes and the server becomes unreachable. We create a dump file from our application process from the task manager when the process memory usage rises to about 23G memory. I use WinDbg to analyze the dump file.

The output of WinDbg is:

0:000> !address -summary

--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free                                    303     7ff8`cd7d7000 ( 127.972 TB)           99.98%
<unknown>                               761        6`f238c000 (  27.785 GB)  96.51%    0.02%
Heap                                   2170        0`2c1ca000 ( 705.789 MB)   2.39%    0.00%
Image                                  1968        0`10600000 ( 262.000 MB)   0.89%    0.00%
Stack                                   180        0`03a80000 (  58.500 MB)   0.20%    0.00%
Other                                    42        0`001ca000 (   1.789 MB)   0.01%    0.00%
TEB                                      60        0`00078000 ( 480.000 kB)   0.00%    0.00%
PEB                                       1        0`00001000 (   4.000 kB)   0.00%    0.00%

--- Type Summary (for busy) ------ RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_PRIVATE                            2980        7`20af1000 (  28.511 GB)  99.03%    0.02%
MEM_IMAGE                              2131        0`11056000 ( 272.336 MB)   0.92%    0.00%
MEM_MAPPED                               71        0`00cd2000 (  12.820 MB)   0.04%    0.00%

--- State Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_FREE                                303     7ff8`cd7d7000 ( 127.972 TB)           99.98%
MEM_COMMIT                             4734        5`ac69d000 (  22.694 GB)  78.83%    0.02%
MEM_RESERVE                             448        1`8617c000 (   6.095 GB)  21.17%    0.00%

--- Protect Summary (for commit) - RgnCount ----------- Total Size -------- %ofBusy %ofTotal
PAGE_READWRITE                         2352        5`9ab71000 (  22.417 GB)  77.87%    0.02%
PAGE_EXECUTE_READ                       152        0`0b1c1000 ( 177.754 MB)   0.60%    0.00%
PAGE_READONLY                           577        0`04a8c000 (  74.547 MB)   0.25%    0.00%
PAGE_WRITECOPY                          629        0`0140e000 (  20.055 MB)   0.07%    0.00%
PAGE_EXECUTE_READWRITE                   39        0`00612000 (   6.070 MB)   0.02%    0.00%
PAGE_NOACCESS                           925        0`0039d000 (   3.613 MB)   0.01%    0.00%
PAGE_READWRITE | PAGE_GUARD              60        0`00122000 (   1.133 MB)   0.00%    0.00%

--- Largest Region by Usage ----------- Base Address -------- Region Size ----------
Free                                    1dc`f2ef0000     7e17`f40e0000 ( 126.094 TB)
<unknown>                              7ff4`e7180000        1`00020000 (   4.000 GB)
Heap                                    1d6`f5d4e000        0`02001000 (  32.004 MB)
Image                                  7ffe`1a114000        0`011cb000 (  17.793 MB)
Stack                                    21`4e100000        0`000fb000 (1004.000 kB)
Other                                   1d6`963f0000        0`00181000 (   1.504 MB)
TEB                                      21`4da40000        0`00002000 (   8.000 kB)
PEB                                      21`4dba7000        0`00001000 (   4.000 kB)

More than 90% of memory usage is in MEM_PRIVATE.

I don't know how to debug what is in this part of memory and how to find the root cause of memory leakage.