rule win_computrace_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        version = "1"
        description = "Detects win.computrace."
        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.computrace"
        malpedia_rule_date = "20221118"
        malpedia_hash = "e0702e2e6d1d00da65c8a29a4ebacd0a4c59e1af"
        malpedia_version = "20221125"
        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 = { 742a a1???????? 3bc3 8b35???????? 7413 6aff }
            // n = 6, score = 200
            //   742a                 | je                  0x2c
            //   a1????????           |                     
            //   3bc3                 | cmp                 eax, ebx
            //   8b35????????         |                     
            //   7413                 | je                  0x15
            //   6aff                 | push                -1

        $sequence_1 = { 7549 56 e8???????? eb41 8d45fc 50 56 }
            // n = 7, score = 200
            //   7549                 | jne                 0x4b
            //   56                   | push                esi
            //   e8????????           |                     
            //   eb41                 | jmp                 0x43
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   50                   | push                eax
            //   56                   | push                esi

        $sequence_2 = { 8d45cc 50 ff15???????? 8d45cc 50 ff15???????? ebd9 }
            // n = 7, score = 200
            //   8d45cc               | lea                 eax, [ebp - 0x34]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8d45cc               | lea                 eax, [ebp - 0x34]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   ebd9                 | jmp                 0xffffffdb

        $sequence_3 = { 753a c705????????02000000 e8???????? 8bf8 a1???????? 57 c7402801000000 }
            // n = 7, score = 200
            //   753a                 | jne                 0x3c
            //   c705????????02000000     |     
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   a1????????           |                     
            //   57                   | push                edi
            //   c7402801000000       | mov                 dword ptr [eax + 0x28], 1

        $sequence_4 = { 32c3 8845f4 8b550c 85d2 740b 8b4dfc }
            // n = 6, score = 200
            //   32c3                 | xor                 al, bl
            //   8845f4               | mov                 byte ptr [ebp - 0xc], al
            //   8b550c               | mov                 edx, dword ptr [ebp + 0xc]
            //   85d2                 | test                edx, edx
            //   740b                 | je                  0xd
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]

        $sequence_5 = { e8???????? 89869c3b0000 5f 8b8e983b0000 8a843158390000 }
            // n = 5, score = 200
            //   e8????????           |                     
            //   89869c3b0000         | mov                 dword ptr [esi + 0x3b9c], eax
            //   5f                   | pop                 edi
            //   8b8e983b0000         | mov                 ecx, dword ptr [esi + 0x3b98]
            //   8a843158390000       | mov                 al, byte ptr [ecx + esi + 0x3958]

        $sequence_6 = { 56 e8???????? 56 e8???????? 0fb64e18 c1e904 80e107 }
            // n = 7, score = 200
            //   56                   | push                esi
            //   e8????????           |                     
            //   56                   | push                esi
            //   e8????????           |                     
            //   0fb64e18             | movzx               ecx, byte ptr [esi + 0x18]
            //   c1e904               | shr                 ecx, 4
            //   80e107               | and                 cl, 7

        $sequence_7 = { f7de 1bf6 46 3bfb 7403 }
            // n = 5, score = 200
            //   f7de                 | neg                 esi
            //   1bf6                 | sbb                 esi, esi
            //   46                   | inc                 esi
            //   3bfb                 | cmp                 edi, ebx
            //   7403                 | je                  5

        $sequence_8 = { 32c1 2470 32c1 8806 c1e804 }
            // n = 5, score = 200
            //   32c1                 | xor                 al, cl
            //   2470                 | and                 al, 0x70
            //   32c1                 | xor                 al, cl
            //   8806                 | mov                 byte ptr [esi], al
            //   c1e804               | shr                 eax, 4

        $sequence_9 = { ff15???????? f7d8 1bc0 40 57 }
            // n = 5, score = 200
            //   ff15????????         |                     
            //   f7d8                 | neg                 eax
            //   1bc0                 | sbb                 eax, eax
            //   40                   | inc                 eax
            //   57                   | push                edi

    condition:
        7 of them and filesize < 73728
}

rule win_computrace_w0 {
    meta:
        author = "ASERT"
        description = "Absolute Computrace Agent Executable"
        reference = "https://asert.arbornetworks.com/lojack-becomes-a-double-agent/#Yara"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.computrace"
        malpedia_version = "20180503"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""

    strings:
        $a = { D1 E0 F5 8B 4D 0C 83 D1 00 8B EC FF 33 83 C3 04 }
        $b1 = { 72 70 63 6E 65 74 70 2E 65 78 65 00 72 70 63 6E 65 74 70 00 }
        $b2 = { 54 61 67 49 64 00 }
    condition:
        $a or ($b1 and $b2)
}