Actor(s): Leviathan
BADFLICK, a backdoor that is capable of modifying the file system, generating a reverse shell, and modifying its command-and-control configuration.
rule win_badflick_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-01-25" version = "1" description = "Detects win.badflick." 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.badflick" malpedia_rule_date = "20230124" malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686" malpedia_version = "20230125" 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 = { 8d440002 50 0fb64508 50 e8???????? ff750c 8bf0 } // n = 7, score = 100 // 8d440002 | lea eax, [eax + eax + 2] // 50 | push eax // 0fb64508 | movzx eax, byte ptr [ebp + 8] // 50 | push eax // e8???????? | // ff750c | push dword ptr [ebp + 0xc] // 8bf0 | mov esi, eax $sequence_1 = { 59 a3???????? 891d???????? ff750c e8???????? 50 } // n = 6, score = 100 // 59 | pop ecx // a3???????? | // 891d???????? | // ff750c | push dword ptr [ebp + 0xc] // e8???????? | // 50 | push eax $sequence_2 = { 57 ff7510 53 eb13 03f8 3b7d10 741a } // n = 7, score = 100 // 57 | push edi // ff7510 | push dword ptr [ebp + 0x10] // 53 | push ebx // eb13 | jmp 0x15 // 03f8 | add edi, eax // 3b7d10 | cmp edi, dword ptr [ebp + 0x10] // 741a | je 0x1c $sequence_3 = { 8d8578fbffff 50 57 ff15???????? 8d8578fbffff 50 ffd6 } // n = 7, score = 100 // 8d8578fbffff | lea eax, [ebp - 0x488] // 50 | push eax // 57 | push edi // ff15???????? | // 8d8578fbffff | lea eax, [ebp - 0x488] // 50 | push eax // ffd6 | call esi $sequence_4 = { 68???????? ff7508 ff15???????? 33c9 83c41c } // n = 5, score = 100 // 68???????? | // ff7508 | push dword ptr [ebp + 8] // ff15???????? | // 33c9 | xor ecx, ecx // 83c41c | add esp, 0x1c $sequence_5 = { 23c8 51 8975ec e8???????? 59 } // n = 5, score = 100 // 23c8 | and ecx, eax // 51 | push ecx // 8975ec | mov dword ptr [ebp - 0x14], esi // e8???????? | // 59 | pop ecx $sequence_6 = { 750d 8d85f8fdffff 50 ff15???????? ff15???????? 5f 5e } // n = 7, score = 100 // 750d | jne 0xf // 8d85f8fdffff | lea eax, [ebp - 0x208] // 50 | push eax // ff15???????? | // ff15???????? | // 5f | pop edi // 5e | pop esi $sequence_7 = { dcc9 dec9 dd1c24 ff75e8 68???????? ff7508 ff15???????? } // n = 7, score = 100 // dcc9 | fmul st(1), st(0) // dec9 | fmulp st(1) // dd1c24 | fstp qword ptr [esp] // ff75e8 | push dword ptr [ebp - 0x18] // 68???????? | // ff7508 | push dword ptr [ebp + 8] // ff15???????? | $sequence_8 = { ffd7 53 e8???????? 59 6a00 8d4508 50 } // n = 7, score = 100 // ffd7 | call edi // 53 | push ebx // e8???????? | // 59 | pop ecx // 6a00 | push 0 // 8d4508 | lea eax, [ebp + 8] // 50 | push eax $sequence_9 = { 8b430d 8945d8 8b4311 8945dc 8b4315 8945e0 } // n = 6, score = 100 // 8b430d | mov eax, dword ptr [ebx + 0xd] // 8945d8 | mov dword ptr [ebp - 0x28], eax // 8b4311 | mov eax, dword ptr [ebx + 0x11] // 8945dc | mov dword ptr [ebp - 0x24], eax // 8b4315 | mov eax, dword ptr [ebx + 0x15] // 8945e0 | mov dword ptr [ebp - 0x20], eax condition: 7 of them and filesize < 81920 }
rule win_badflick_w0 { meta: description = "Detects BADFLICK backdoor" author = "@VK_Intel" reference = "BADFLICK backdoor" date = "2018-03-26" hash = "7ba05abdf8f0323aa30c3d52e22df951eb5b67a2620014336eab7907b0a5cedf" reference = "https://www.fireeye.com/blog/threat-research/2018/03/suspected-chinese-espionage-group-targeting-maritime-and-engineering-industries.html" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.badflick" malpedia_version = "20180407" malpedia_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: $s0 = "%s\\en-US\\cmd.exe.mui" fullword wide $s1 = "[Green] pid=%d tid=%d modulePath=%s|" fullword wide $s2 = "1|103.243.175.181|80|5|xxxxxxxxxxxxxxxxxxxxxxx" wide ascii $s3 = "modulePath=%[^|]" fullword wide $s4 = "%s:%d:%s:%d:%d" fullword ascii $s5 = "regsvr32 %s %s %s go \"%s\"" fullword wide $s6 = "modulePath=" fullword wide $s7 = "%d %d.%d.%d %s" fullword wide $s8 = "winMain static green" fullword wide $s9 = "o%d Core %.2f GHz" fullword wide $s10 = "6&62676=6B6G6N6c6s6" fullword ascii $op0 = { 8b 54 24 54 8b cf 2b cb 8d 04 0a 3b c7 76 02 8b } $op1 = { a1 08 77 40 00 89 45 94 8d 45 94 50 ff 35 04 77 } $op2 = { 8b 7c 24 14 8b f7 2b f5 8d 64 24 00 8a 1f 84 db } condition: uint16(0) == 0x5a4d and filesize < 108KB and 8 of ($s*) and 1 of ($op*) }
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