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GameService Server Authentication Keep-Alive Challenge

Summary

This packet is believed to serve as both a keep-alive and as an authentication/security challenge for the client.

The first challenge is sent within 2 minutes of the user logging in to the server, and then every 5 minutes exactly thereafter.

The response is Gameservice Client 0x0088 Authentication Keep-Alive Response.

Structure

gameservice_server_00d7_authentication_keepalive_challenge

Name Type Summary
unknown_token u2 Unchanging over the course of a single session. Identical in response. Might be some sort of key.
server_id u2 ID of the server currently connected to.
challenge_length u4 Seen lengths of 52 (0x34), 60 (0x3C), and 68 (0x44) bytes.
challenge_data bytes[challenge_length] Concerning PangyaTH, The first 16 bytes barely change at all across all known examples. The next 2 sets of 8 bytes can often remain consistent for up to an hour before changing, and repetitions/reuse of the latter set of 8 bytes have been witnessed across a 3 hour timespan in 2019. The remaining length is completely different on each challenge.

Definition

meta:
  id: gameservice_server_00d7_authentication_keepalive_challenge
  title: GameService Server Authentication Keep-Alive Challenge
  encoding: ASCII
  endian: le
  imports:
    - ../../common/pstring
seq:
  - id: unknown_token
    type: u2
  - id: server_id
    type: u2
  - id: challenge_length
    type: u4
  - id: challenge_data
    size: challenge_length

Examples

Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040
00000050

packetId = 215
d7 00 
data > unknownToken = 28529
71 6f 
data > serverId = 20217
f9 4e 
data > challengeLength = 76
4c 00 00 00 
data > challengeData = 12,71,41,145,39,142,82,34,54,213,120,179,72,28,161,68,223,189,8,196,169,172,175,197,165,224,155,95,57,159,71,87,87,161,158,66,214,185,40,192,94,105,90,167,235,250,252,34,183,169,12,112,20,108,195,55,87,170,170,111,56,210,75,169,144,197,51,178,2,249,39,172,167,9,7,103
0c 47 29 91 27 8e 
52 22 36 d5 78 b3 48 1c a1 44 df bd 08 c4 a9 ac 
af c5 a5 e0 9b 5f 39 9f 47 57 57 a1 9e 42 d6 b9 
28 c0 5e 69 5a a7 eb fa fc 22 b7 a9 0c 70 14 6c 
c3 37 57 aa aa 6f 38 d2 4b a9 90 c5 33 b2 02 f9 
27 ac a7 09 07 67 
..qo.NL....G).'.
R"6.x.H..D......
....._9.GWW..B..
(.^iZ...."...p.l
.7W..o8.K...3...
'....g
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040
00000050

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 76
4c 00 00 00 
data > challengeData = 12,71,41,145,39,142,82,34,54,213,120,179,72,28,161,68,57,142,117,162,77,149,23,226,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,86,99,55,141,177,46,156,146,124,177,191,77,70,238,107,39,48,29,27,206,131,184,162,33,251,54,208,0,173,69,194,176,255,127,147,19
0c 47 29 91 27 8e 
52 22 36 d5 78 b3 48 1c a1 44 39 8e 75 a2 4d 95 
17 e2 08 01 43 4f bd ee 29 dc a9 0d 81 1b 46 bb 
06 3a 56 63 37 8d b1 2e 9c 92 7c b1 bf 4d 46 ee 
6b 27 30 1d 1b ce 83 b8 a2 21 fb 36 d0 00 ad 45 
c2 b0 ff 7f 93 13 
...g.NL....G).'.
R"6.x.H..D9.u.M.
....CO..).....F.
.:Vc7.....|..MF.
k'0......!.6...E
.....
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 52
34 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,212,243,122,117,150,169,101,53,18,238,133,97,236,19,36,3,151,231,219,184
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a d4 f3 7a 75 96 a9 
65 35 12 ee 85 61 ec 13 24 03 97 e7 db b8 
...g.N4....G).&.
P"6.x.H..D..CO..
).....F..:..zu..
e5...a..$.....
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 68
44 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,25,200,233,121,0,9,164,156,132,131,118,210,240,251,176,249,77,197,152,186,55,90,67,35,68,52,183,38,220,186,247,70,119,218,219,66
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a 19 c8 e9 79 00 09 
a4 9c 84 83 76 d2 f0 fb b0 f9 4d c5 98 ba 37 5a 
43 23 44 34 b7 26 dc ba f7 46 77 da db 42 
...g.ND....G).&.
P"6.x.H..D..CO..
).....F..:...y..
....v.....M...7Z
C#D4.&...Fw..B
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 68
44 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,188,189,16,249,162,172,150,126,235,132,205,80,104,74,29,62,113,212,114,189,116,221,77,106,224,194,59,139,12,191,107,84,175,92,131,93
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a bc bd 10 f9 a2 ac 
96 7e eb 84 cd 50 68 4a 1d 3e 71 d4 72 bd 74 dd 
4d 6a e0 c2 3b 8b 0c bf 6b 54 af 5c 83 5d 
...g.ND....G).&.
P"6.x.H..D..CO..
).....F..:......
.~...PhJ.>q.r.t.
Mj..;...kT.\.]
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 60
3c 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,225,141,120,72,47,59,110,53,119,59,214,170,224,70,3,57,164,222,53,83,197,100,4,66,151,232,7,191
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a e1 8d 78 48 2f 3b 
6e 35 77 3b d6 aa e0 46 03 39 a4 de 35 53 c5 64 
04 42 97 e8 07 bf 
...g.N<....G).&.
P"6.x.H..D..CO..
).....F..:..xH/;
n5w;...F.9..5S.d
.B....
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 60
3c 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,170,192,227,138,142,10,90,45,164,54,35,75,47,215,204,175,182,138,183,68,64,22,208,91,111,125,63,85
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a aa c0 e3 8a 8e 0a 
5a 2d a4 36 23 4b 2f d7 cc af b6 8a b7 44 40 16 
d0 5b 6f 7d 3f 55 
...g.N<....G).&.
P"6.x.H..D..CO..
).....F..:......
Z-.6#K/......D@.
.[o}?U
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 26584
d8 67 
data > serverId = 20212
f4 4e 
data > challengeLength = 60
3c 00 00 00 
data > challengeData = 12,71,41,145,38,142,80,34,54,213,120,179,72,28,161,68,8,1,67,79,189,238,41,220,169,13,129,27,70,187,6,58,247,48,27,185,237,55,220,60,114,173,63,232,208,238,147,233,231,60,208,130,82,51,203,42,239,0,203,12
0c 47 29 91 26 8e 
50 22 36 d5 78 b3 48 1c a1 44 08 01 43 4f bd ee 
29 dc a9 0d 81 1b 46 bb 06 3a f7 30 1b b9 ed 37 
dc 3c 72 ad 3f e8 d0 ee 93 e9 e7 3c d0 82 52 33 
cb 2a ef 00 cb 0c 
...g.N<....G).&.
P"6.x.H..D..CO..
).....F..:.0...7
..?......<..R3
.*....
Agent: TH.R6.829.01 
00000000
00000010
00000020
00000030
00000040

packetId = 215
d7 00 
data > unknownToken = 31723
eb 7b 
data > serverId = 20217
f9 4e 
data > challengeLength = 68
44 00 00 00 
data > challengeData = 12,71,41,145,39,142,82,34,54,213,120,179,72,28,161,68,194,229,215,19,165,129,135,227,75,24,93,228,217,245,60,224,87,161,158,66,214,185,40,192,250,65,180,130,162,201,139,130,186,63,5,19,240,202,45,141,90,220,107,65,245,249,192,159,135,52,63,223
0c 47 29 91 27 8e 
52 22 36 d5 78 b3 48 1c a1 44 c2 e5 d7 13 a5 81 
87 e3 4b 18 5d e4 d9 f5 3c e0 57 a1 9e 42 d6 b9 
28 c0 fa 41 b4 82 a2 c9 8b 82 ba 3f 05 13 f0 ca 
2d 8d 5a dc 6b 41 f5 f9 c0 9f 87 34 3f df 
...{.ND....G).'.
R"6.x.H..D......
..K.]...<.W..B..
(..A.......?....
-.Z.kA.....4?.