rule win_remexi_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        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 = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 8945e4 8945e8 b802000000 51 668945dc ff15???????? }
            // n = 6, score = 200
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   b802000000           | mov                 eax, 2
            //   51                   | push                ecx
            //   668945dc             | mov                 word ptr [ebp - 0x24], ax
            //   ff15????????         |                     

        $sequence_2 = { 8907 894704 894708 6a01 89470c 57 894710 }
            // n = 7, 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
            //   57                   | push                edi
            //   894710               | mov                 dword ptr [edi + 0x10], eax

        $sequence_3 = { 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_4 = { 53 50 ff15???????? 3dffffff00 }
            // n = 4, score = 200
            //   53                   | push                ebx
            //   50                   | push                eax
            //   ff15????????         |                     
            //   3dffffff00           | cmp                 eax, 0xffffff

        $sequence_5 = { 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_6 = { c705????????01000000 c705????????00000000 ff15???????? 8b0d???????? 51 }
            // n = 5, score = 200
            //   c705????????01000000     |     
            //   c705????????00000000     |     
            //   ff15????????         |                     
            //   8b0d????????         |                     
            //   51                   | push                ecx

        $sequence_7 = { 68???????? 41 50 a3???????? c705????????02000000 890d???????? ffd6 }
            // n = 7, score = 200
            //   68????????           |                     
            //   41                   | inc                 ecx
            //   50                   | push                eax
            //   a3????????           |                     
            //   c705????????02000000     |     
            //   890d????????         |                     
            //   ffd6                 | call                esi

        $sequence_8 = { 8b4818 8b5104 50 8955e0 }
            // n = 4, score = 200
            //   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_9 = { 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_10 = { 57 894710 ff15???????? 6a00 }
            // n = 4, score = 200
            //   57                   | push                edi
            //   894710               | mov                 dword ptr [edi + 0x10], eax
            //   ff15????????         |                     
            //   6a00                 | push                0

        $sequence_11 = { 8b95d4feffff 52 6a00 68ffff1f00 ffd7 }
            // n = 5, score = 200
            //   8b95d4feffff         | mov                 edx, dword ptr [ebp - 0x12c]
            //   52                   | push                edx
            //   6a00                 | push                0
            //   68ffff1f00           | push                0x1fffff
            //   ffd7                 | call                edi

        $sequence_12 = { 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_13 = { 771a 488d0c92 48c1e103 e8???????? 488bf8 }
            // n = 5, score = 100
            //   771a                 | mov                 dword ptr [ebx - 0x18], edx
            //   488d0c92             | mov                 ecx, 0x28
            //   48c1e103             | dec                 eax
            //   e8????????           |                     
            //   488bf8               | mov                 esi, eax

        $sequence_14 = { 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_15 = { 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_16 = { 4883bc249800000010 720d 488b8c2480000000 e8???????? 84db }
            // n = 5, score = 100
            //   4883bc249800000010     | jb    0xffffffef
            //   720d                 | je                  0x23
            //   488b8c2480000000     | dec                 eax
            //   e8????????           |                     
            //   84db                 | lea                 ecx, [0x2878a]

        $sequence_17 = { 488d4d08 e8???????? 90 48895c2458 b900000c07 }
            // n = 5, score = 100
            //   488d4d08             | inc                 ecx
            //   e8????????           |                     
            //   90                   | mov                 eax, 5
            //   48895c2458           | dec                 ecx
            //   b900000c07           | cmp                 ebx, eax

        $sequence_18 = { 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_19 = { 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_20 = { 488be9 498953e8 b928000000 e8???????? 488bf0 }
            // n = 5, score = 100
            //   488be9               | lea                 ecx, [ebp + 8]
            //   498953e8             | nop                 
            //   b928000000           | dec                 eax
            //   e8????????           |                     
            //   488bf0               | mov                 dword ptr [esp + 0x58], ebx

        $sequence_21 = { 72ed 48833d????????00 741f 488d0d8a870200 }
            // n = 4, score = 100
            //   72ed                 | mov                 ecx, 0x70c0000
            //   48833d????????00     |                     
            //   741f                 | dec                 eax
            //   488d0d8a870200       | lea                 ecx, [ebx + 8]

        $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 = { 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_24 = { 488d4b08 e8???????? 90 488d4d08 e8???????? }
            // n = 5, score = 100
            //   488d4b08             | dec                 esp
            //   e8????????           |                     
            //   90                   | cmovb               eax, ebx
            //   488d4d08             | dec                 eax
            //   e8????????           |                     

        $sequence_25 = { 488b5810 4883781810 7203 488b00 41b805000000 493bd8 4c0f42c3 }
            // n = 7, score = 100
            //   488b5810             | dec                 eax
            //   4883781810           | mov                 ebx, dword ptr [eax + 0x10]
            //   7203                 | dec                 eax
            //   488b00               | cmp                 dword ptr [eax + 0x18], 0x10
            //   41b805000000         | jb                  5
            //   493bd8               | dec                 eax
            //   4c0f42c3             | mov                 eax, dword ptr [eax]

        $sequence_26 = { 488bf9 4889542460 c744245000000000 c644247000 33c0 6689442471 }
            // n = 6, score = 100
            //   488bf9               | nop                 
            //   4889542460           | dec                 eax
            //   c744245000000000     | lea                 ecx, [ebp + 8]
            //   c644247000           | dec                 eax
            //   33c0                 | mov                 ebp, ecx
            //   6689442471           | dec                 ecx

        $sequence_27 = { 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]

    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*))
}