SYMBOLCOMMON_NAMEaka. SYNONYMS
win.cobint (Back to overview)

CobInt

aka: COOLPANTS

Actor(s): Cobalt

VTCollection    

CobInt, is a self-developed backdoor of the Cobalt group. The modular tool has capabilities to collect initial intelligence information about the compromised machine and stream video from its desktop. If the operator decides that the system is of interest, the backdoor will download and launch CobaltStrike framework stager. It's CRM mailslot module was also observed being downloaded by ISFB.

References
2020-06-16PTSecurityPT ESC Threat Intelligence
Cobalt: tactics and tools update
CobInt
2020-03-04CrowdStrikeCrowdStrike
2020 CrowdStrike Global Threat Report
MESSAGETAP More_eggs 8.t Dropper Anchor BabyShark BadNews Clop Cobalt Strike CobInt Cobra Carbon System Cutwail DanaBot Dharma DoppelDridex DoppelPaymer Dridex Emotet FlawedAmmyy FriedEx Gandcrab Get2 IcedID ISFB KerrDown LightNeuron LockerGoga Maze MECHANICAL Necurs Nokki Outlook Backdoor Phobos Predator The Thief QakBot REvil RobinHood Ryuk SDBbot Skipper SmokeLoader TerraRecon TerraStealer TerraTV TinyLoader TrickBot Vidar Winnti ANTHROPOID SPIDER APT23 APT31 APT39 APT40 BlackTech BuhTrap Charming Kitten CLOCKWORK SPIDER DOPPEL SPIDER FIN7 Gamaredon Group GOBLIN PANDA MONTY SPIDER MUSTANG PANDA NARWHAL SPIDER NOCTURNAL SPIDER PINCHY SPIDER SALTY SPIDER SCULLY SPIDER SMOKY SPIDER Thrip VENOM SPIDER VICEROY TIGER
2020-03-03PWC UKPWC UK
Cyber Threats 2019:A Year in Retrospect
KevDroid MESSAGETAP magecart AndroMut Cobalt Strike CobInt Crimson RAT DNSpionage Dridex Dtrack Emotet FlawedAmmyy FlawedGrace FriedEx Gandcrab Get2 GlobeImposter Grateful POS ISFB Kazuar LockerGoga Nokki QakBot Ramnit REvil Rifdoor RokRAT Ryuk shadowhammer ShadowPad Shifu Skipper StoneDrill Stuxnet TrickBot Winnti ZeroCleare APT41 MUSTANG PANDA Sea Turtle
2020-01-01SecureworksSecureWorks
GOLD KINGSWOOD
More_eggs ATMSpitter Cobalt Strike CobInt MimiKatz
2020-01-01SecureworksSecureWorks
GOLD KINGSWOOD
More_eggs ATMSpitter Cobalt Strike CobInt MimiKatz Cobalt
2018-09-11ProofpointProofpoint Staff
New modular downloaders fingerprint systems - Part 3: CobInt
CobInt
2018-08-30NetScoutASERT Team
Double the Infection, Double the Fun
More_eggs CobInt
2018-08-30NetScoutASERT Team
Double the Infection, Double the Fun
CobInt
2018-05-29Group-IBRustam Mirkasymov
Cobalt Renaissance: new attacks and joint operations
CobInt
Yara Rules
[TLP:WHITE] win_cobint_auto (20251219 | Detects win.cobint.)
rule win_cobint_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-01-05"
        version = "1"
        description = "Detects win.cobint."
        info = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.6.0"
        signator_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.cobint"
        malpedia_rule_date = "20260105"
        malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79"
        malpedia_version = "20251219"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    /* DISCLAIMER
     * The strings used in this rule have been automatically selected from the
     * disassembly of memory dumps and unpacked files, using YARA-Signator.
     * The code and documentation is published here:
     * https://github.com/fxb-cocacoding/yara-signator
     * As Malpedia is used as data source, please note that for a given
     * number of families, only single samples are documented.
     * This likely impacts the degree of generalization these rules will offer.
     * Take the described generation method also into consideration when you
     * apply the rules in your use cases and assign them confidence levels.
     */


    strings:
        $sequence_0 = { 83c418 a1???????? 03c9 891cc8 8b0d???????? a1???????? }
            // n = 6, score = 400
            //   83c418               | add                 esp, 0x18
            //   a1????????           |                     
            //   03c9                 | add                 ecx, ecx
            //   891cc8               | mov                 dword ptr [eax + ecx*8], ebx
            //   8b0d????????         |                     
            //   a1????????           |                     

        $sequence_1 = { 891cc8 8b0d???????? a1???????? 03c9 8974c804 8b0d???????? }
            // n = 6, score = 400
            //   891cc8               | mov                 dword ptr [eax + ecx*8], ebx
            //   8b0d????????         |                     
            //   a1????????           |                     
            //   03c9                 | add                 ecx, ecx
            //   8974c804             | mov                 dword ptr [eax + ecx*8 + 4], esi
            //   8b0d????????         |                     

        $sequence_2 = { c745f404000000 50 8d4508 50 6805000020 56 }
            // n = 6, score = 400
            //   c745f404000000       | mov                 dword ptr [ebp - 0xc], 4
            //   50                   | push                eax
            //   8d4508               | lea                 eax, [ebp + 8]
            //   50                   | push                eax
            //   6805000020           | push                0x20000005
            //   56                   | push                esi

        $sequence_3 = { 50 8d45f4 50 8d45ec 50 6813000020 ff75f0 }
            // n = 7, score = 400
            //   50                   | push                eax
            //   8d45f4               | lea                 eax, [ebp - 0xc]
            //   50                   | push                eax
            //   8d45ec               | lea                 eax, [ebp - 0x14]
            //   50                   | push                eax
            //   6813000020           | push                0x20000013
            //   ff75f0               | push                dword ptr [ebp - 0x10]

        $sequence_4 = { 57 6a65 eb31 85db 743a }
            // n = 5, score = 400
            //   57                   | push                edi
            //   6a65                 | push                0x65
            //   eb31                 | jmp                 0x33
            //   85db                 | test                ebx, ebx
            //   743a                 | je                  0x3c

        $sequence_5 = { e8???????? 83c410 eb60 6a01 8d450f }
            // n = 5, score = 400
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   eb60                 | jmp                 0x62
            //   6a01                 | push                1
            //   8d450f               | lea                 eax, [ebp + 0xf]

        $sequence_6 = { 57 bf00020000 57 e8???????? 57 6a00 }
            // n = 6, score = 400
            //   57                   | push                edi
            //   bf00020000           | mov                 edi, 0x200
            //   57                   | push                edi
            //   e8????????           |                     
            //   57                   | push                edi
            //   6a00                 | push                0

        $sequence_7 = { 83f820 7cf3 eb07 8bf0 c1e604 03f2 57 }
            // n = 7, score = 400
            //   83f820               | cmp                 eax, 0x20
            //   7cf3                 | jl                  0xfffffff5
            //   eb07                 | jmp                 9
            //   8bf0                 | mov                 esi, eax
            //   c1e604               | shl                 esi, 4
            //   03f2                 | add                 esi, edx
            //   57                   | push                edi

        $sequence_8 = { 740d 8b5508 0355f0 8a45ec }
            // n = 4, score = 200
            //   740d                 | je                  0xf
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   0355f0               | add                 edx, dword ptr [ebp - 0x10]
            //   8a45ec               | mov                 al, byte ptr [ebp - 0x14]

        $sequence_9 = { 31b7807c30ae 807c909090 90 bdfd807c90 }
            // n = 4, score = 200
            //   31b7807c30ae         | xor                 dword ptr [edi - 0x51cf8380], esi
            //   807c909090           | cmp                 byte ptr [eax + edx*4 - 0x70], 0x90
            //   90                   | nop                 
            //   bdfd807c90           | mov                 ebp, 0x907c80fd

        $sequence_10 = { 8bcb 897db8 e8???????? 8bf0 }
            // n = 4, score = 200
            //   8bcb                 | mov                 ecx, ebx
            //   897db8               | mov                 dword ptr [ebp - 0x48], edi
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_11 = { 81ffea968891 740a 33c0 8b12 85d2 }
            // n = 5, score = 200
            //   81ffea968891         | cmp                 edi, 0x918896ea
            //   740a                 | je                  0xc
            //   33c0                 | xor                 eax, eax
            //   8b12                 | mov                 edx, dword ptr [edx]
            //   85d2                 | test                edx, edx

        $sequence_12 = { ffd6 eb03 8b75e4 ff75d8 ffd6 }
            // n = 5, score = 200
            //   ffd6                 | call                esi
            //   eb03                 | jmp                 5
            //   8b75e4               | mov                 esi, dword ptr [ebp - 0x1c]
            //   ff75d8               | push                dword ptr [ebp - 0x28]
            //   ffd6                 | call                esi

        $sequence_13 = { 395318 763c 8b3c90 33c0 03fe }
            // n = 5, score = 200
            //   395318               | cmp                 dword ptr [ebx + 0x18], edx
            //   763c                 | jbe                 0x3e
            //   8b3c90               | mov                 edi, dword ptr [eax + edx*4]
            //   33c0                 | xor                 eax, eax
            //   03fe                 | add                 edi, esi

        $sequence_14 = { 90 90 90 e10b }
            // n = 4, score = 200
            //   90                   | nop                 
            //   90                   | nop                 
            //   90                   | nop                 
            //   e10b                 | loope               0xd

        $sequence_15 = { b800a80000 2bc7 50 56 53 ff55f8 85c0 }
            // n = 7, score = 200
            //   b800a80000           | mov                 eax, 0xa800
            //   2bc7                 | sub                 eax, edi
            //   50                   | push                eax
            //   56                   | push                esi
            //   53                   | push                ebx
            //   ff55f8               | call                dword ptr [ebp - 8]
            //   85c0                 | test                eax, eax

        $sequence_16 = { 8802 eb0b 8b4d08 034df0 }
            // n = 4, score = 200
            //   8802                 | mov                 byte ptr [edx], al
            //   eb0b                 | jmp                 0xd
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   034df0               | add                 ecx, dword ptr [ebp - 0x10]

        $sequence_17 = { bffc807c28 1a807c170e81 7cd7 9b 807c909090 90 90 }
            // n = 7, score = 200
            //   bffc807c28           | mov                 edi, 0x287c80fc
            //   1a807c170e81         | sbb                 al, byte ptr [eax - 0x7ef1e884]
            //   7cd7                 | jl                  0xffffffd9
            //   9b                   | wait                
            //   807c909090           | cmp                 byte ptr [eax + edx*4 - 0x70], 0x90
            //   90                   | nop                 
            //   90                   | nop                 

        $sequence_18 = { 749b 807ce19a80 7c90 90 }
            // n = 4, score = 200
            //   749b                 | je                  0xffffff9d
            //   807ce19a80           | cmp                 byte ptr [ecx - 0x66], 0x80
            //   7c90                 | jl                  0xffffff92
            //   90                   | nop                 

        $sequence_19 = { 90 e10b 96 7c90 90 }
            // n = 5, score = 200
            //   90                   | nop                 
            //   e10b                 | loope               0xd
            //   96                   | xchg                eax, esi
            //   7c90                 | jl                  0xffffff92
            //   90                   | nop                 

        $sequence_20 = { bab1c50790 8bf0 33ff e8???????? 8d4dec 8945f8 }
            // n = 6, score = 200
            //   bab1c50790           | mov                 edx, 0x9007c5b1
            //   8bf0                 | mov                 esi, eax
            //   33ff                 | xor                 edi, edi
            //   e8????????           |                     
            //   8d4dec               | lea                 ecx, [ebp - 0x14]
            //   8945f8               | mov                 dword ptr [ebp - 8], eax

        $sequence_21 = { ffd0 85c0 0f8406010000 8b4de0 ba6a62f095 }
            // n = 5, score = 200
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax
            //   0f8406010000         | je                  0x10c
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   ba6a62f095           | mov                 edx, 0x95f0626a

        $sequence_22 = { e8???????? 8945f8 8d45c4 50 }
            // n = 4, score = 200
            //   e8????????           |                     
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   8d45c4               | lea                 eax, [ebp - 0x3c]
            //   50                   | push                eax

        $sequence_23 = { e8???????? 58 83c005 c3 31b7807c30ae }
            // n = 5, score = 200
            //   e8????????           |                     
            //   58                   | pop                 eax
            //   83c005               | add                 eax, 5
            //   c3                   | ret                 
            //   31b7807c30ae         | xor                 dword ptr [edi - 0x51cf8380], esi

    condition:
        7 of them and filesize < 65536
}
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