rule win_remexi_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.remexi."
        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.remexi"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { 56 c706ffffffff e8???????? 83c404 }
            // n = 4, score = 300
            //   56                   | push                esi
            //   c706ffffffff         | mov                 dword ptr [esi], 0xffffffff
            //   e8????????           |                     
            //   83c404               | add                 esp, 4

        $sequence_1 = { 50 ff15???????? 8b0d???????? 8b35???????? 890d???????? }
            // n = 5, score = 200
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b0d????????         |                     
            //   8b35????????         |                     
            //   890d????????         |                     

        $sequence_2 = { ff15???????? 6a10 8d4ddc 8bf0 51 56 ff15???????? }
            // n = 7, score = 200
            //   ff15????????         |                     
            //   6a10                 | push                0x10
            //   8d4ddc               | lea                 ecx, [ebp - 0x24]
            //   8bf0                 | mov                 esi, eax
            //   51                   | push                ecx
            //   56                   | push                esi
            //   ff15????????         |                     

        $sequence_3 = { 41 50 a3???????? c705????????02000000 890d???????? ffd6 }
            // n = 6, score = 200
            //   41                   | inc                 ecx
            //   50                   | push                eax
            //   a3????????           |                     
            //   c705????????02000000     |     
            //   890d????????         |                     
            //   ffd6                 | call                esi

        $sequence_4 = { e8???????? 83ec1c 8bcc 89642430 6aff 53 }
            // n = 6, score = 200
            //   e8????????           |                     
            //   83ec1c               | sub                 esp, 0x1c
            //   8bcc                 | mov                 ecx, esp
            //   89642430             | mov                 dword ptr [esp + 0x30], esp
            //   6aff                 | push                -1
            //   53                   | push                ebx

        $sequence_5 = { 8945e8 b802000000 51 668945dc }
            // n = 4, score = 200
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   b802000000           | mov                 eax, 2
            //   51                   | push                ecx
            //   668945dc             | mov                 word ptr [ebp - 0x24], ax

        $sequence_6 = { 8b45d8 8b4818 8b5104 50 8955e0 }
            // n = 5, score = 200
            //   8b45d8               | mov                 eax, dword ptr [ebp - 0x28]
            //   8b4818               | mov                 ecx, dword ptr [eax + 0x18]
            //   8b5104               | mov                 edx, dword ptr [ecx + 4]
            //   50                   | push                eax
            //   8955e0               | mov                 dword ptr [ebp - 0x20], edx

        $sequence_7 = { 8907 894704 894708 6a01 89470c }
            // n = 5, score = 200
            //   8907                 | mov                 dword ptr [edi], eax
            //   894704               | mov                 dword ptr [edi + 4], eax
            //   894708               | mov                 dword ptr [edi + 8], eax
            //   6a01                 | push                1
            //   89470c               | mov                 dword ptr [edi + 0xc], eax

        $sequence_8 = { ff15???????? 8bf0 85f6 7513 8b45d8 }
            // n = 5, score = 200
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   7513                 | jne                 0x15
            //   8b45d8               | mov                 eax, dword ptr [ebp - 0x28]

        $sequence_9 = { 53 50 ff15???????? 3dffffff00 }
            // n = 4, score = 200
            //   53                   | push                ebx
            //   50                   | push                eax
            //   ff15????????         |                     
            //   3dffffff00           | cmp                 eax, 0xffffff

        $sequence_10 = { 53 83cbff 57 8b3d???????? }
            // n = 4, score = 200
            //   53                   | push                ebx
            //   83cbff               | or                  ebx, 0xffffffff
            //   57                   | push                edi
            //   8b3d????????         |                     

        $sequence_11 = { c705????????ffffffff c705????????01000000 c705????????00000000 ffd6 83ffff 7407 }
            // n = 6, score = 200
            //   c705????????ffffffff     |     
            //   c705????????01000000     |     
            //   c705????????00000000     |     
            //   ffd6                 | call                esi
            //   83ffff               | cmp                 edi, -1
            //   7407                 | je                  9

        $sequence_12 = { 8945e0 8945e4 8945e8 b802000000 }
            // n = 4, score = 200
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   b802000000           | mov                 eax, 2

        $sequence_13 = { 014b30 bf???????? b903000000 8b742418 }
            // n = 4, score = 100
            //   014b30               | add                 dword ptr [ebx + 0x30], ecx
            //   bf????????           |                     
            //   b903000000           | mov                 ecx, 3
            //   8b742418             | mov                 esi, dword ptr [esp + 0x18]

        $sequence_14 = { 488d058da00100 c3 4053 4883ec20 488bd9 488d0d7ca00100 483bd9 }
            // n = 7, score = 100
            //   488d058da00100       | dec                 eax
            //   c3                   | mov                 ecx, dword ptr [esp + 0x70]
            //   4053                 | dec                 eax
            //   4883ec20             | mov                 dword ptr [esp + 0x88], 0xf
            //   488bd9               | dec                 eax
            //   488d0d7ca00100       | mov                 dword ptr [esp + 0x80], 0
            //   483bd9               | mov                 byte ptr [esp + 0x70], 0

        $sequence_15 = { 015330 41 894b0c e9???????? }
            // n = 4, score = 100
            //   015330               | add                 dword ptr [ebx + 0x30], edx
            //   41                   | inc                 ecx
            //   894b0c               | mov                 dword ptr [ebx + 0xc], ecx
            //   e9????????           |                     

        $sequence_16 = { 015330 e9???????? 8b5314 3b5318 0f8d23020000 }
            // n = 5, score = 100
            //   015330               | add                 dword ptr [ebx + 0x30], edx
            //   e9????????           |                     
            //   8b5314               | mov                 edx, dword ptr [ebx + 0x14]
            //   3b5318               | cmp                 edx, dword ptr [ebx + 0x18]
            //   0f8d23020000         | jge                 0x229

        $sequence_17 = { 015930 3b542408 0f8d10ffffff 8d3c52 }
            // n = 4, score = 100
            //   015930               | add                 dword ptr [ecx + 0x30], ebx
            //   3b542408             | cmp                 edx, dword ptr [esp + 8]
            //   0f8d10ffffff         | jge                 0xffffff16
            //   8d3c52               | lea                 edi, [edx + edx*2]

        $sequence_18 = { 488b8c24a0000000 e8???????? 48c78424b80000000f000000 4c89bc24b0000000 c68424a000000000 }
            // n = 5, score = 100
            //   488b8c24a0000000     | cmp                 eax, -3
            //   e8????????           |                     
            //   48c78424b80000000f000000     | ja    0x1a
            //   4c89bc24b0000000     | test                eax, eax
            //   c68424a000000000     | jne                 0x14

        $sequence_19 = { 488b4c2470 e8???????? 48c78424880000000f000000 48c784248000000000000000 c644247000 41b806000000 488d151b3d0200 }
            // n = 7, score = 100
            //   488b4c2470           | nop                 
            //   e8????????           |                     
            //   48c78424880000000f000000     | dec    eax
            //   48c784248000000000000000     | mov    ecx, dword ptr [ecx]
            //   c644247000           | dec                 eax
            //   41b806000000         | lea                 eax, [ecx - 1]
            //   488d151b3d0200       | dec                 eax

        $sequence_20 = { 016b04 83c41c 5b 5e }
            // n = 4, score = 100
            //   016b04               | add                 dword ptr [ebx + 4], ebp
            //   83c41c               | add                 esp, 0x1c
            //   5b                   | pop                 ebx
            //   5e                   | pop                 esi

        $sequence_21 = { 488d15c7780200 480f45d0 881f 381a 740e 4883cbff 90 }
            // n = 7, score = 100
            //   488d15c7780200       | inc                 ecx
            //   480f45d0             | mov                 ecx, edx
            //   881f                 | cdq                 
            //   381a                 | sub                 eax, edx
            //   740e                 | dec                 eax
            //   4883cbff             | lea                 edx, [0x278c7]
            //   90                   | dec                 eax

        $sequence_22 = { 015518 8b5d14 85db 0f8565fbffff }
            // n = 4, score = 100
            //   015518               | add                 dword ptr [ebp + 0x18], edx
            //   8b5d14               | mov                 ebx, dword ptr [ebp + 0x14]
            //   85db                 | test                ebx, ebx
            //   0f8565fbffff         | jne                 0xfffffb6b

        $sequence_23 = { 488b09 488d41ff 4883f8fd 7714 ff15???????? 85c0 750a }
            // n = 7, score = 100
            //   488b09               | cmovne              edx, eax
            //   488d41ff             | mov                 byte ptr [edi], bl
            //   4883f8fd             | cmp                 byte ptr [edx], bl
            //   7714                 | je                  0x14
            //   ff15????????         |                     
            //   85c0                 | dec                 eax
            //   750a                 | or                  ebx, 0xffffffff

        $sequence_24 = { 015330 8a10 eb84 8a5001 }
            // n = 4, score = 100
            //   015330               | add                 dword ptr [ebx + 0x30], edx
            //   8a10                 | mov                 dl, byte ptr [eax]
            //   eb84                 | jmp                 0xffffff86
            //   8a5001               | mov                 dl, byte ptr [eax + 1]

        $sequence_25 = { 7532 b902010209 e8???????? 90 48837b1810 7208 }
            // n = 6, score = 100
            //   7532                 | jne                 0x34
            //   b902010209           | mov                 ecx, 0x9020102
            //   e8????????           |                     
            //   90                   | nop                 
            //   48837b1810           | dec                 eax
            //   7208                 | cmp                 dword ptr [ebx + 0x18], 0x10

        $sequence_26 = { 438d0401 4c8d1d31490100 418bca 99 2bc2 }
            // n = 5, score = 100
            //   438d0401             | jb                  0xa
            //   4c8d1d31490100       | inc                 ebx
            //   418bca               | lea                 eax, [ecx + eax]
            //   99                   | dec                 esp
            //   2bc2                 | lea                 ebx, [0x14931]

        $sequence_27 = { 016b24 89e8 83c44c 5b }
            // n = 4, score = 100
            //   016b24               | add                 dword ptr [ebx + 0x24], ebp
            //   89e8                 | mov                 eax, ebp
            //   83c44c               | add                 esp, 0x4c
            //   5b                   | pop                 ebx

        $sequence_28 = { 488b01 8a08 880a 33c9 488d1c32 4c8d05c71a0100 }
            // n = 6, score = 100
            //   488b01               | inc                 ecx
            //   8a08                 | mov                 eax, 6
            //   880a                 | dec                 eax
            //   33c9                 | lea                 edx, [0x23d1b]
            //   488d1c32             | dec                 eax
            //   4c8d05c71a0100       | mov                 ecx, dword ptr [esp + 0xa0]

    condition:
        7 of them and filesize < 614400
}

rule win_remexi_w0 {
    meta:
        author = "Symantec"
        source = "http://www.symantec.com/content/en/us/enterprise/media/security_response/docs/CadelSpy-Remexi-IOC.pdf"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.remexi"
        malpedia_version = "20170410"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""
    strings:
        $c1   = { 00 3C 65 78 69 74 3E 00 }    /* <exit>  */
        $c2   = { 00 3C 69 64 3E 00 }          /* <id>    */
        $c3   = { 00 3C 72 65 6D 3E 00 }       /* <rem>   */
        $c4   = { 00 3C 63 6C 6F 73 65 3E 00}  /* <close> */
        $c5   = { 00 57 49 4E 00 }             /* WIN     */
        $c6   = { 00 63 6D 64 2E 65 78 65 00 } /* cmd.exe */
        $c7   = { 00 49 44 00 }                /* ID      */ 
        $c8   = { 00 72 65 6D 00 }             /* rem     */
        $d1   = "\\SEA.pdb"
        $d2   = "\\mas.pdb"
        $s1  = "Connecting to the server..."
        $s2  = "cmd.exe /c sc stop sea & sc start sea"
        $s3  = "SYSTEM\\CurrentControlSet\\services\\SEA\\Parameters"
        $s4  = "RecvWrit()-Read_Sock-Failed"
        $s5  = "ReadPipeSendSock()"
    condition:
        (4 of ($c*) and (2 of ($s*) or any of ($d*))) or (5 of ($c*) and any of ($s*))
}