Reversing WoWs Resource Format - Part 2/5: Looking For The Metadata

August 25, 2025 - 9 mins read

Searching & Reading The Metadata

In Part 1, we discovered:

Data lives in res_packages/ as custom .pkg archives.
Each .pkg is a sequence of DEFLATE-compressed blobs separated by 64-bit IDs with zero padding.
No file names inside .pkg; names/paths must exist elsewhere (in indexes).

Now we need to find where and how the file and directory structure is stored.

Back To File Exploration

The metadata hopefully isn’t embedded in executables. Let’s search:

# List all files
# then remove uninteresting bits like replays, crashes, DLLs, logs, .pkg
# or CEF stuff (embedded Chrome used for the armory, inventory, dockyard and clan base))

kakwa@linux Games/World of Warships » find ./ -type f | grep -v cef | grep -v replays \
    | grep -v crashes | grep -v '.pkg' | grep -v '.dll' | grep -v '.log' \
    | grep -v '\.exe' | less

[...]
./bin/6775398/res/texts/pl/LC_MESSAGES/global.mo
./bin/6775398/res/texts/zh_tw/LC_MESSAGES/global.mo
./bin/6775398/res/texts/fr/LC_MESSAGES/global.mo
./bin/6775398/res/texts/zh_sg/LC_MESSAGES/global.mo
./bin/6775398/res/camerasConsumer.xml
./bin/6775398/bin32/paths.xml
./bin/6775398/bin32/Licenses.txt
./bin/6775398/bin32/monitor_config.json
./bin/6775398/bin64/paths.xml
./bin/6775398/bin64/Licenses.txt
./bin/6775398/bin64/monitor_config.json
[...]
./bin/6775398/idx/spaces_dock_dry.idx
./bin/6775398/idx/spaces_dock_hsf.idx
./bin/6775398/idx/spaces_sea_hope.idx
./bin/6775398/idx/vehicles_pve.idx
./bin/6775398/idx/vehicles_level8_fr.idx
./bin/6775398/idx/vehicles_level5_panasia.idx
[...]

The .idx files look promising, especially their names match the .pkg files:

spaces_dock_hsf.idx → spaces_dock_hsf_0001.pkg
vehicles_level9_ned.idx → vehicles_level9_ned_0001.pkg

Checking We Have The Metadata

Let’s take a look:

kakwa@linux bin/6775398/idx » strings -n 5 system_data.idx

#%B'E
E)zj'
FM'lb
%}n:b
(	?A+
c|'lY
zc78'
tKDStorage.bin
waves_heights1.dds
animatedMiscs.xml
LowerDeck.dds
[...]
maps
highlight_noise.dds
space_variation_dummy.dds
waves_heights0.dds
4F$)p
:M+Xp
F?mep
wsystem_data_0001.pkg
[...]

Bingo, we have all the file names, and at the end, the name of the corresponding .pkg file.

These .idx files, as the extension indicates, are our indexes containing all the file names and metadata.

Also, note that we have a few names (like maps or helpers) without extensions, these are probably directory names.

Note: bin/ directory and game versions

The ./bin directory contains build-numbered subdirectories (5241351, 6081105, etc.), with WoWs keeping the current and previous builds. We’ll use the highest number for the latest indexes.

General Layout Of the Index File

Let’s examine an index file:

kakwa@linux 6775398/idx » hexdump -C system_data.idx | less

00000000  49 53 46 50 00 00 00 02  91 9d 39 b4 40 00 00 00  |ISFP......9.@...|
00000010  37 01 00 00 1c 01 00 00  01 00 00 00 00 00 00 00  |7...............|
00000020  28 00 00 00 00 00 00 00  f6 3b 00 00 00 00 00 00  |(........;......|
00000030  36 71 00 00 00 00 00 00  0e 00 00 00 00 00 00 00  |6q..............|
00000040  e0 26 00 00 00 00 00 00  8f 0c 9a ba 4f 40 b6 93  |.&..........O@..|
00000050  27 b9 08 b1 d1 a1 b1 db  13 00 00 00 00 00 00 00  |'...............|
00000060  ce 26 00 00 00 00 00 00  8f ec 87 4a 28 d0 f7 c7  |.&.........J(...|
00000070  a4 eb 1b 3e 50 21 d8 74  12 00 00 00 00 00 00 00  |...>P!.t........|
00000080  c1 26 00 00 00 00 00 00  ad 70 a2 e7 ac 2c 4f 6b  |.&.......p...,Ok|
00000090  27 b9 08 b1 d1 a1 b1 db  0e 00 00 00 00 00 00 00  |'...............|
000000a0  b3 26 00 00 00 00 00 00  4e 84 a5 6a 94 dc 1f 7f  |.&......N..j....|
000000b0  62 f5 aa 4b 5e 15 7f 93  10 00 00 00 00 00 00 00  |b..K^...........|
000000c0  a1 26 00 00 00 00 00 00  4e b0 fe 23 62 40 a5 65  |.&......N..#b@.e|
000000d0  27 b9 08 b1 d1 a1 b1 db  20 00 00 00 00 00 00 00  |'....... .......|
000000e0  91 26 00 00 00 00 00 00  8e c7 6a 58 7c 86 62 33  |.&........jX|.b3|
000000f0  27 b9 08 b1 d1 a1 b1 db  0f 00 00 00 00 00 00 00  |'...............|
00000100  91 26 00 00 00 00 00 00  8e 43 3d e9 cf 49 52 a4  |.&.......C=..IR.|
00000110  62 f5 aa 4b 5e 15 7f 93  16 00 00 00 00 00 00 00  |b..K^...........|
00000120  80 26 00 00 00 00 00 00  0e 3c 9a 6d 22 de 7b da  |.&.......<.m".{.|
00000130  4e b0 fe 23 62 40 a5 65  0b 00 00 00 00 00 00 00  |N..#b@.e........|
00000140  76 26 00 00 00 00 00 00  0e 48 58 ea 50 44 1a 47  |v&.......HX.PD.G|
00000150  df 61 50 67 c7 3a dd 7a  13 00 00 00 00 00 00 00  |.aPg.:.z........|
00000160  61 26 00 00 00 00 00 00  e0 9f c3 bd d2 12 20 04  |a&............ .|
00000170  09 28 f1 df 2d 04 93 de  0b 00 00 00 00 00 00 00  |.(..-...........|
00000180  54 26 00 00 00 00 00 00  e0 95 53 f6 cc 08 c0 46  |T&........S....F|
00000190  06 cf 85 bd 69 99 e2 46  0d 00 00 00 00 00 00 00  |....i..F........|
000001a0  3f 26 00 00 00 00 00 00  e0 99 68 5e 2d 70 13 72  |?&........h^-p.r|
000001b0  4c d1 2e 30 73 38 d9 13  10 00 00 00 00 00 00 00  |L..0s8..........|
[...]
000026c0  0d 15 00 00 00 00 00 00  ce 6a 28 bc cf e7 79 c8  |.........j(...y.|
000026d0  a4 eb 1b 3e 50 21 d8 74  1a 00 00 00 00 00 00 00  |...>P!.t........|
000026e0  01 15 00 00 00 00 00 00  6c c0 c9 f7 7e 00 03 05  |........l...~...|
000026f0  a4 eb 1b 3e 50 21 d8 74  13 00 00 00 00 00 00 00  |...>P!.t........|
00002700  fb 14 00 00 00 00 00 00  74 d1 1b 8d f4 ff 7a ce  |........t.....z.|
00002710  a4 eb 1b 3e 50 21 d8 74  4b 44 53 74 6f 72 61 67  |...>P!.tKDStorag|
00002720  65 2e 62 69 6e 00 77 61  76 65 73 5f 68 65 69 67  |e.bin.waves_heig|
00002730  68 74 73 31 2e 64 64 73  00 61 6e 69 6d 61 74 65  |hts1.dds.animate|
00002740  64 4d 69 73 63 73 2e 78  6d 6c 00 4c 6f 77 65 72  |dMiscs.xml.Lower|
00002750  44 65 63 6b 2e 64 64 73  00 63 6f 6d 6d 61 6e 64  |Deck.dds.command|
[...]
00003bc0  2e 64 64 73 00 68 69 67  68 6c 69 67 68 74 5f 6e  |.dds.highlight_n|
00003bd0  6f 69 73 65 2e 64 64 73  00 73 70 61 63 65 5f 76  |oise.dds.space_v|
00003be0  61 72 69 61 74 69 6f 6e  5f 64 75 6d 6d 79 2e 64  |ariation_dummy.d|
00003bf0  64 73 00 77 61 76 65 73  5f 68 65 69 67 68 74 73  |ds.waves_heights|
00003c00  30 2e 64 64 73 00 8f 0c  9a ba 4f 40 b6 93 70 11  |0.dds.....O@..p.|
00003c10  03 07 0d 33 ed 77 00 00  00 00 00 00 00 00 05 00  |...3.w..........|
00003c20  00 00 01 00 00 00 f5 21  00 00 bf 00 45 5c 6c 36  |.......!....E\l6|
00003c30  00 00 00 00 00 00 8f ec  87 4a 28 d0 f7 c7 70 11  |.........J(...p.|
00003c40  03 07 0d 33 ed 77 1e 9b  ef 05 00 00 00 00 05 00  |...3.w..........|
00003c50  00 00 01 00 00 00 15 15  01 00 03 77 63 97 3e ab  |...........wc.>.|
00003c60  02 00 00 00 00 00 ad 70  a2 e7 ac 2c 4f 6b 70 11  |.......p...,Okp.|
00003c70  03 07 0d 33 ed 77 05 22  00 00 00 00 00 00 05 00  |...3.w."........|
00003c80  00 00 01 00 00 00 cb 01  00 00 6d b9 de c1 ad 0c  |..........m.....|
[...]
000070a0  00 00 01 00 00 00 90 24  00 00 62 c1 d9 06 f8 d8  |.......$..b.....|
000070b0  00 00 00 00 00 00 57 b3  82 06 56 f0 2a e6 70 11  |......W...V.*.p.|
000070c0  03 07 0d 33 ed 77 ea cc  15 0a 00 00 00 00 05 00  |...3.w..........|
000070d0  00 00 01 00 00 00 7c 01  00 00 84 a8 12 1d 61 04  |......|.......a.|
000070e0  00 00 00 00 00 00 57 64  91 29 c9 3c f0 96 70 11  |......Wd.).<..p.|
000070f0  03 07 0d 33 ed 77 a9 ef  15 0a 00 00 00 00 05 00  |...3.w..........|
00007100  00 00 01 00 00 00 6f 09  00 00 fc 56 94 f8 9a 37  |......o....V...7|
00007110  00 00 00 00 00 00 21 67  ac 70 22 ec ca b8 70 11  |......!g.p"...p.|
00007120  03 07 0d 33 ed 77 28 f9  15 0a 00 00 00 00 05 00  |...3.w(.........|
00007130  00 00 01 00 00 00 0b 2d  00 00 03 bd b0 50 67 e9  |.......-.....Pg.|
00007140  00 00 00 00 00 00 15 00  00 00 00 00 00 00 18 00  |................|
00007150  00 00 00 00 00 00 70 11  03 07 0d 33 ed 77 73 79  |......p....3.wsy|
00007160  73 74 65 6d 5f 64 61 74  61 5f 30 30 30 31 2e 70  |stem_data_0001.p|
00007170  6b 67 00                                          |kg.|

The general layout of the file appears to be at least in 3 chunks:

A first chunk of metadata
All the file name strings \0-separated, but also a few strings without extensions, probably directory names
A second chunk of metadata

Let’s look for the IDs we found in the corresponding .pkg (here system_data_0001.pkg), for example 00 00 00 00 | bf 00 45 5c | 6c 36 00 00 | 00 00 00 00.

[......................] 00 8f 0c  9a ba 4f 40 b6 93 70 11  |0.dds.....O@..p.|
00003c10  03 07 0d 33 ed 77 00 00  00 00 00 00 00 00 05 00  |...3.w..........|
00003c20  00 00 01 00 00 00 f5 21  00 00 bf 00 45 5c 6c 36  |.......!....E\l6|
00003c30  00 00 00 00 00 00 8f ec [...]

Ok, it’s there, in the second chunk. And it also works if we test for other IDs. We have at least a link by ID between the .idx and the .pkg file.

We will come back later to the second chunk, remembering that, but let’s focus on the first chunk for now.

Recap (Part 2)

Identified .idx files in ./bin/<latest>/idx/ as indexes for .pkg archives and matched them by name.
Determine that that the index is constituted of 5 parts:
- Header
- Metadata section
- Names
- Records section
- Footer

In the next part of this series we will reverse the index file format in details.