rule win_computrace_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        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 = "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 = { 8d45cc 50 ff75dc 8d8540f2ffff 50 ff75d8 53 }
            // n = 7, score = 200
            //   8d45cc               | lea                 eax, [ebp - 0x34]
            //   50                   | push                eax
            //   ff75dc               | push                dword ptr [ebp - 0x24]
            //   8d8540f2ffff         | lea                 eax, [ebp - 0xdc0]
            //   50                   | push                eax
            //   ff75d8               | push                dword ptr [ebp - 0x28]
            //   53                   | push                ebx

        $sequence_1 = { 53 53 56 e8???????? ebd5 }
            // n = 5, score = 200
            //   53                   | push                ebx
            //   53                   | push                ebx
            //   56                   | push                esi
            //   e8????????           |                     
            //   ebd5                 | jmp                 0xffffffd7

        $sequence_2 = { 0f85fbfeffff 8d8558ffffff 50 e8???????? 397de4 7420 }
            // n = 6, score = 200
            //   0f85fbfeffff         | jne                 0xffffff01
            //   8d8558ffffff         | lea                 eax, [ebp - 0xa8]
            //   50                   | push                eax
            //   e8????????           |                     
            //   397de4               | cmp                 dword ptr [ebp - 0x1c], edi
            //   7420                 | je                  0x22

        $sequence_3 = { 7433 817de413010000 750b 8b8658440000 3b45e8 741f 8d45e0 }
            // n = 7, score = 200
            //   7433                 | je                  0x35
            //   817de413010000       | cmp                 dword ptr [ebp - 0x1c], 0x113
            //   750b                 | jne                 0xd
            //   8b8658440000         | mov                 eax, dword ptr [esi + 0x4458]
            //   3b45e8               | cmp                 eax, dword ptr [ebp - 0x18]
            //   741f                 | je                  0x21
            //   8d45e0               | lea                 eax, [ebp - 0x20]

        $sequence_4 = { 3bf3 7505 83f8ff 750f 53 53 }
            // n = 6, score = 200
            //   3bf3                 | cmp                 esi, ebx
            //   7505                 | jne                 7
            //   83f8ff               | cmp                 eax, -1
            //   750f                 | jne                 0x11
            //   53                   | push                ebx
            //   53                   | push                ebx

        $sequence_5 = { 8d7e20 e8???????? 8d83401b0000 8bc8 2b8b481b0000 }
            // n = 5, score = 200
            //   8d7e20               | lea                 edi, [esi + 0x20]
            //   e8????????           |                     
            //   8d83401b0000         | lea                 eax, [ebx + 0x1b40]
            //   8bc8                 | mov                 ecx, eax
            //   2b8b481b0000         | sub                 ecx, dword ptr [ebx + 0x1b48]

        $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 = { 48 7407 035d0c 8a1b eb19 8a5e1a eb1e }
            // n = 7, score = 200
            //   48                   | dec                 eax
            //   7407                 | je                  9
            //   035d0c               | add                 ebx, dword ptr [ebp + 0xc]
            //   8a1b                 | mov                 bl, byte ptr [ebx]
            //   eb19                 | jmp                 0x1b
            //   8a5e1a               | mov                 bl, byte ptr [esi + 0x1a]
            //   eb1e                 | jmp                 0x20

        $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 = { 897dfc 397dd8 7507 57 53 }
            // n = 5, score = 200
            //   897dfc               | mov                 dword ptr [ebp - 4], edi
            //   397dd8               | cmp                 dword ptr [ebp - 0x28], edi
            //   7507                 | jne                 9
            //   57                   | push                edi
            //   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)
}