Server ULevel::NotifyReceivedText crash (Linux server)

[King Sumo]

Yesterday my server randomly crashed several times - below is the callstack:

Log: 
Developer Backtrace:
Log: [ 1]  ./ucc-bin-real() [0x8669527]
Log: [ 2]  [0xb7792400]
Log: [ 3]  /lib/i686/cmov/libc.so.6(memcpy+0x5a) [0xb7568c9a]
Log: [ 4]  ./steamclient_linux.so(+0x395503) [0xb4241503]
Log: [ 5]  ./steamclient_linux.so(+0x348706) [0xb41f4706]
Log: [ 6]  ./steamclient_linux.so(+0x3955e0) [0xb42415e0]
Log: [ 7]  ./steamclient_linux.so(+0x34a7d2) [0xb41f67d2]
Log: [ 8]  ./steamclient_linux.so(+0x347126) [0xb41f3126]
Log: [ 9]  ./steamclient_linux.so(+0x3b851e) [0xb426451e]
Log: [10]  ./steamclient_linux.so(+0x3bc2df) [0xb42682df]
Log: [11]  ./steamclient_linux.so(+0x3be2fa) [0xb426a2fa]
Log: [12]  ./steamclient_linux.so(+0x3d28f4) [0xb427e8f4]
Log: [13]  ./steamclient_linux.so(+0x347e9f) [0xb41f3e9f]
Log: [14]  ./steamclient_linux.so(+0x292c4e) [0xb413ec4e]
Log: [15]  ./steamclient_linux.so(+0x1ca86c) [0xb407686c]
Log: [16]  ./steamclient_linux.so(+0x12b57a) [0xb3fd757a]
Log: [17]  ./steamclient_linux.so(+0x163a91) [0xb400fa91]
Log: [18]  ./steamclient_linux.so(+0x1cc119) [0xb4078119]
Log: [19]  ./steamclient_linux.so(+0x1ae26e) [0xb405a26e]
Log: [20]  ./steamclient_linux.so(+0x1ccf50) [0xb4078f50]
Log: [21]  ./steamclient_linux.so(+0x1ae4ad) [0xb405a4ad]
Log: [22]  ./steamclient_linux.so(+0x1aeb18) [0xb405ab18]
Log: [23]  ./steamclient_linux.so(+0x1aebb9) [0xb405abb9]
Log: [24]  ./libtier0_s_linux.so(CatchAndWriteMiniDumpForVoidPtrFn+0x17) [0xb3e79a89]
Log: [25]  ./steamclient_linux.so(+0x1ae8e0) [0xb405a8e0]
Log: [26]  ./libtier0_s_linux.so(_ZN7CThread10ThreadProcEPv+0x16b) [0xb3e7bb47]
Log: [27]  /lib/i686/cmov/libpthread.so.0(+0x5955) [0xb7770955]
Log: [28]  /lib/i686/cmov/libc.so.6(clone+0x5e) [0xb75c05ee]
Log: Unreal Call Stack: ULevel::NotifyReceivedText <- UControlChannel::ReceivedBunch <- UChannel::ReceivedSequencedBunch <- Direct <- UChannel::ReceivedRawBunch <- DispatchDataToChannel <- BunchData <- UNetConnection::ReceivedPacket <- UNetConnection::ReceivedRawPacket <- UTcpNetDriver::TickDispatch <- UpdatePreNet <- ULevel::Tick <- TickLevel <- UGameEngine::Tick <- UpdateWorld <- UServerCommandlet::Main
Exit: Exiting.

I think this could be caused by some client. How to prevent this?

PS. it is possible to detect/block the attack by using SNORT - anyone sorted this?

 

[King Sumo]

Still having random crashes:

1
4353a50a32b59399933548ef818ae4f5
11
15889
1347467778
wcs07
6
1
0
1
3339 (128.29)
0
Aug 24 2012 15:54:49
KF-SBC-BoxWithoutHope?game=KFmod.KFGameType?VACSecured=true?MaxPlayers=15?AdminName=Sumo?AdminPassword=xxxxx?multihome=server07.wcsgames.com.br?Mutator=AdminPlus_v2_KF.MutAdminPlus,ServerPerksMut.ServerPerksMut,SumoSP.SumoSP,MutKFAntiBlocker.MutKFAntiBlocker,KFPatHPLeft.MutPatHPLeft,MutSlotMachine.MutSlotMachine,KFNadeWarn.MutNadeWarn,KFSumoMutV3.KFSumoMutV3,KFNHolyHandGrenade.KFNHolyHandGrenade,KFARGBuchonOPQ.KFARGBuchonOPQ,AutoSpawnerO2.AutoSpawnerO2,KFOPortalTurret5.KFOPortalTurret5,KFGiveWeapon.KFGiveWeapon,KFFakedPlayersEx.KFFakedPlayersEx,KFSAlarmTrader.KFSAlarmTrader,KFBossSquadB3.KFBossSquad,WeldArmor_v10_O3.weldarmor,KFDoorMessagesV1.KFDoorMessagesV1,MutVisibleSpecs.MutVisSpecs,AFKMut.AFKMut?Difficulty=4 -nohomedir ini=KillingFloor.ini
14326.297852
ULevel::NotifyReceivedText <- UControlChannel::ReceivedBunch <- UChannel::ReceivedSequencedBunch <- Direct <- UChannel::ReceivedRawBunch <- DispatchDataToChannel <- BunchData <- UNetConnection::ReceivedPacket <- UNetConnection::ReceivedRawPacket <- UTcpNetDriver::TickDispatch <- UpdatePreNet <- ULevel::Tick <- TickLevel <- UGameEngine::Tick <- UpdateWorld <- UServerCommandlet::Main
1 ./ucc-bin-real() [0x8669b17],
2 [0xb7794400],
3 /lib/i686/cmov/libc.so.6(memcpy+0x5a) [0xb7565c9a],
4 ./steamclient_linux.so(+0x395503) [0xb459c503],
5 ./steamclient_linux.so(+0x348706) [0xb454f706],
6 ./steamclient_linux.so(+0x3955e0) [0xb459c5e0],
7 ./steamclient_linux.so(+0x34a7d2) [0xb45517d2],
8 ./steamclient_linux.so(+0x347126) [0xb454e126],
9 ./steamclient_linux.so(+0x3b851e) [0xb45bf51e],
10 ./steamclient_linux.so(+0x3bc2df) [0xb45c32df],
11 ./steamclient_linux.so(+0x3be2fa) [0xb45c52fa],
12 ./steamclient_linux.so(+0x3d28f4) [0xb45d98f4],
13 ./steamclient_linux.so(+0x347e9f) [0xb454ee9f],
14 ./steamclient_linux.so(+0x292c4e) [0xb4499c4e],
15 ./steamclient_linux.so(+0x1ca86c) [0xb43d186c],
16 ./steamclient_linux.so(+0x12b57a) [0xb433257a],
17 ./steamclient_linux.so(+0x163a91) [0xb436aa91],
18 ./steamclient_linux.so(+0x1cc119) [0xb43d3119],
19 ./steamclient_linux.so(+0x1ae26e) [0xb43b526e],
20 ./steamclient_linux.so(+0x1ccf50) [0xb43d3f50],
21 ./steamclient_linux.so(+0x1ae4ad) [0xb43b54ad],
22 ./steamclient_linux.so(+0x1aeb18) [0xb43b5b18],
23 ./steamclient_linux.so(+0x1aebb9) [0xb43b5bb9],
24 ./libtier0_s_linux.so(CatchAndWriteMiniDumpForVoidPtrFn+0x17) [0xb41d4a89],
25 ./steamclient_linux.so(+0x1ae8e0) [0xb43b58e0],
26 ./libtier0_s_linux.so(_ZN7CThread10ThreadProcEPv+0x16b) [0xb41d6b47],
27 /lib/i686/cmov/libpthread.so.0(+0x5955) [0xb776d955],
28 /lib/i686/cmov/libc.so.6(clone+0x5e) [0xb75bd5ee]

I think this is a security issue and probably can be exploitable (buffer overflow in memcpy)... It happens randomly when a user tries to connect to the server.