rule win_computrace_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        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 = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 = { 03c7 6a00 51 50 56 e8???????? 03f8 }
            // n = 7, score = 200
            //   03c7                 | add                 eax, edi
            //   6a00                 | push                0
            //   51                   | push                ecx
            //   50                   | push                eax
            //   56                   | push                esi
            //   e8????????           |                     
            //   03f8                 | add                 edi, eax

        $sequence_1 = { eb1a 8afb 80e777 387e18 }
            // n = 4, score = 200
            //   eb1a                 | jmp                 0x1c
            //   8afb                 | mov                 bh, bl
            //   80e777               | and                 bh, 0x77
            //   387e18               | cmp                 byte ptr [esi + 0x18], bh

        $sequence_2 = { 740e 837de400 7408 037de4 897dd8 eba6 8b4514 }
            // n = 7, score = 200
            //   740e                 | je                  0x10
            //   837de400             | cmp                 dword ptr [ebp - 0x1c], 0
            //   7408                 | je                  0xa
            //   037de4               | add                 edi, dword ptr [ebp - 0x1c]
            //   897dd8               | mov                 dword ptr [ebp - 0x28], edi
            //   eba6                 | jmp                 0xffffffa8
            //   8b4514               | mov                 eax, dword ptr [ebp + 0x14]

        $sequence_3 = { 6a02 56 e8???????? 53 8d45e0 50 ff75e0 }
            // n = 7, score = 200
            //   6a02                 | push                2
            //   56                   | push                esi
            //   e8????????           |                     
            //   53                   | push                ebx
            //   8d45e0               | lea                 eax, dword ptr [ebp - 0x20]
            //   50                   | push                eax
            //   ff75e0               | push                dword ptr [ebp - 0x20]

        $sequence_4 = { 833d????????00 56 751f 6a00 8d85fcfeffff 50 e8???????? }
            // n = 7, score = 200
            //   833d????????00       |                     
            //   56                   | push                esi
            //   751f                 | jne                 0x21
            //   6a00                 | push                0
            //   8d85fcfeffff         | lea                 eax, dword ptr [ebp - 0x104]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_5 = { 8945d8 837dd8ff 743e 837dd800 }
            // n = 4, score = 200
            //   8945d8               | mov                 dword ptr [ebp - 0x28], eax
            //   837dd8ff             | cmp                 dword ptr [ebp - 0x28], -1
            //   743e                 | je                  0x40
            //   837dd800             | cmp                 dword ptr [ebp - 0x28], 0

        $sequence_6 = { 381d???????? 8a00 7508 381d???????? 7424 a804 7420 }
            // n = 7, score = 200
            //   381d????????         |                     
            //   8a00                 | mov                 al, byte ptr [eax]
            //   7508                 | jne                 0xa
            //   381d????????         |                     
            //   7424                 | je                  0x26
            //   a804                 | test                al, 4
            //   7420                 | je                  0x22

        $sequence_7 = { 68???????? e8???????? 8365e400 6af4 ff15???????? 8bd8 8365fc00 }
            // n = 7, score = 200
            //   68????????           |                     
            //   e8????????           |                     
            //   8365e400             | and                 dword ptr [ebp - 0x1c], 0
            //   6af4                 | push                -0xc
            //   ff15????????         |                     
            //   8bd8                 | mov                 ebx, eax
            //   8365fc00             | and                 dword ptr [ebp - 4], 0

        $sequence_8 = { 894104 8b5004 85d2 7504 8901 }
            // n = 5, score = 200
            //   894104               | mov                 dword ptr [ecx + 4], eax
            //   8b5004               | mov                 edx, dword ptr [eax + 4]
            //   85d2                 | test                edx, edx
            //   7504                 | jne                 6
            //   8901                 | mov                 dword ptr [ecx], eax

        $sequence_9 = { 56 8b742408 8d8e441b0000 8a01 a801 747d 53 }
            // n = 7, score = 200
            //   56                   | push                esi
            //   8b742408             | mov                 esi, dword ptr [esp + 8]
            //   8d8e441b0000         | lea                 ecx, dword ptr [esi + 0x1b44]
            //   8a01                 | mov                 al, byte ptr [ecx]
            //   a801                 | test                al, 1
            //   747d                 | je                  0x7f
            //   53                   | push                ebx

    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)
}