SYMBOLCOMMON_NAMEaka. SYNONYMS
win.moonbounce (Back to overview)

MoonBounce

Actor(s): APT41


MoonBounce is a malware embedded into a modified UEFI firmware. Placed into SPI flash, it can provide persistence across full reinstall and even disk replacements. MoonBounce deploys user-mode malware through in-memory staging with a small footprint.

References
2022-05-27PTSecurityAnton Belousov, Aleksey Vishnyakov
@online{belousov:20220527:how:d00c942, author = {Anton Belousov and Aleksey Vishnyakov}, title = {{How bootkits are implemented in modern firmware and how UEFI differs from Legacy BIOS}}, date = {2022-05-27}, organization = {PTSecurity}, url = {https://habr.com/ru/amp/post/668154/}, language = {Russian}, urldate = {2022-05-29} } How bootkits are implemented in modern firmware and how UEFI differs from Legacy BIOS
LoJax MoonBounce
2022-01-21binarlyBinarly Team
@online{team:20220121:deeper:14be956, author = {Binarly Team}, title = {{A deeper UEFI dive into MoonBounce}}, date = {2022-01-21}, organization = {binarly}, url = {https://www.binarly.io/posts/A_deeper_UEFI_dive_into_MoonBounce/index.html}, language = {English}, urldate = {2022-01-25} } A deeper UEFI dive into MoonBounce
MoonBounce
2022-01-20KasperskyMark Lechtik, Vasily Berdnikov, Denis Legezo, Ilya Borisov
@online{lechtik:20220120:moonbounce:cd173f1, author = {Mark Lechtik and Vasily Berdnikov and Denis Legezo and Ilya Borisov}, title = {{MoonBounce: the dark side of UEFI firmware}}, date = {2022-01-20}, organization = {Kaspersky}, url = {https://securelist.com/moonbounce-the-dark-side-of-uefi-firmware/105468/}, language = {English}, urldate = {2022-01-24} } MoonBounce: the dark side of UEFI firmware
MoonBounce
2022-01-20Kaspersky LabsMark Lechtik, Vasily Berdnikov, Denis Legezo, Ilya Borisov
@techreport{lechtik:20220120:technical:fa16a24, author = {Mark Lechtik and Vasily Berdnikov and Denis Legezo and Ilya Borisov}, title = {{Technical details of MoonBounce’s implementation}}, date = {2022-01-20}, institution = {Kaspersky Labs}, url = {https://media.kasperskycontenthub.com/wp-content/uploads/sites/43/2022/01/19115831/MoonBounce_technical-details_eng.pdf}, language = {English}, urldate = {2022-01-25} } Technical details of MoonBounce’s implementation
MoonBounce
Yara Rules
[TLP:WHITE] win_moonbounce_auto (20221125 | Detects win.moonbounce.)
rule win_moonbounce_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        version = "1"
        description = "Detects win.moonbounce."
        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.moonbounce"
        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 = { 6800100000 ff7654 53 ff5708 }
            // n = 4, score = 100
            //   6800100000           | push                0x1000
            //   ff7654               | push                dword ptr [esi + 0x54]
            //   53                   | push                ebx
            //   ff5708               | call                dword ptr [edi + 8]

        $sequence_1 = { 50 ff570c 8945f0 85c0 747a 8b4df8 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   ff570c               | call                dword ptr [edi + 0xc]
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   85c0                 | test                eax, eax
            //   747a                 | je                  0x7c
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]

        $sequence_2 = { 8b4310 33f6 56 6a01 83c040 }
            // n = 5, score = 100
            //   8b4310               | mov                 eax, dword ptr [ebx + 0x10]
            //   33f6                 | xor                 esi, esi
            //   56                   | push                esi
            //   6a01                 | push                1
            //   83c040               | add                 eax, 0x40

        $sequence_3 = { d1e9 394df4 72c2 034004 83780400 }
            // n = 5, score = 100
            //   d1e9                 | shr                 ecx, 1
            //   394df4               | cmp                 dword ptr [ebp - 0xc], ecx
            //   72c2                 | jb                  0xffffffc4
            //   034004               | add                 eax, dword ptr [eax + 4]
            //   83780400             | cmp                 dword ptr [eax + 4], 0

        $sequence_4 = { 85c0 743b 7907 25ffff0000 eb05 }
            // n = 5, score = 100
            //   85c0                 | test                eax, eax
            //   743b                 | je                  0x3d
            //   7907                 | jns                 9
            //   25ffff0000           | and                 eax, 0xffff
            //   eb05                 | jmp                 7

        $sequence_5 = { 83450804 85c0 75ce eb04 }
            // n = 4, score = 100
            //   83450804             | add                 dword ptr [ebp + 8], 4
            //   85c0                 | test                eax, eax
            //   75ce                 | jne                 0xffffffd0
            //   eb04                 | jmp                 6

        $sequence_6 = { 034004 83780400 7798 8d8680000000 83780400 c745f401000000 0f86a7000000 }
            // n = 7, score = 100
            //   034004               | add                 eax, dword ptr [eax + 4]
            //   83780400             | cmp                 dword ptr [eax + 4], 0
            //   7798                 | ja                  0xffffff9a
            //   8d8680000000         | lea                 eax, [esi + 0x80]
            //   83780400             | cmp                 dword ptr [eax + 4], 0
            //   c745f401000000       | mov                 dword ptr [ebp - 0xc], 1
            //   0f86a7000000         | jbe                 0xad

        $sequence_7 = { 83ec18 837d0800 0f8440010000 8b4510 f70000010000 }
            // n = 5, score = 100
            //   83ec18               | sub                 esp, 0x18
            //   837d0800             | cmp                 dword ptr [ebp + 8], 0
            //   0f8440010000         | je                  0x146
            //   8b4510               | mov                 eax, dword ptr [ebp + 0x10]
            //   f70000010000         | test                dword ptr [eax], 0x100

        $sequence_8 = { 50 ffd7 84c0 7518 8b4310 56 6a01 }
            // n = 7, score = 100
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   84c0                 | test                al, al
            //   7518                 | jne                 0x1a
            //   8b4310               | mov                 eax, dword ptr [ebx + 0x10]
            //   56                   | push                esi
            //   6a01                 | push                1

        $sequence_9 = { 8b3d???????? 6a00 6a01 ff7508 }
            // n = 4, score = 100
            //   8b3d????????         |                     
            //   6a00                 | push                0
            //   6a01                 | push                1
            //   ff7508               | push                dword ptr [ebp + 8]

    condition:
        7 of them and filesize < 70912
}
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