Actor(s): IcePeony
According to nao_sec, this malware is a simple passive-mode backdoor that is installed as a service.
rule win_ice_event_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-01-05" version = "1" description = "Detects win.ice_event." 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.ice_event" malpedia_rule_date = "20260105" malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79" malpedia_version = "20251219" 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 = { 48c74424780f000000 c644246000 488b4598 4883f810 } // n = 4, score = 100 // 48c74424780f000000 | test eax, eax // c644246000 | je 0x4b7 // 488b4598 | dec eax // 4883f810 | lea edx, [0x1ba80] $sequence_1 = { 3b0d???????? 7326 4863c9 488d15b4080100 488bc1 83e13f } // n = 6, score = 100 // 3b0d???????? | // 7326 | dec eax // 4863c9 | mov edx, ebx // 488d15b4080100 | dec eax // 488bc1 | lea ecx, [0x1dd6f] // 83e13f | xor ecx, ecx $sequence_2 = { 48c743180f000000 c60300 8bc6 488b4c2478 4833cc e8???????? 4c8d9c2480000000 } // n = 7, score = 100 // 48c743180f000000 | dec eax // c60300 | lea eax, [0xaed9] // 8bc6 | dec eax // 488b4c2478 | mov dword ptr [ebp + 0xf], eax // 4833cc | dec eax // e8???????? | // 4c8d9c2480000000 | lea eax, [0xaede] $sequence_3 = { 4863f8 4803f7 4983c9ff 4c8bc7 488d542430 488d4dc8 } // n = 6, score = 100 // 4863f8 | dec esp // 4803f7 | sub eax, ecx // 4983c9ff | dec eax // 4c8bc7 | sub esi, ebp // 488d542430 | dec esp // 488d4dc8 | lea esi, [esi + esi] $sequence_4 = { 4156 4883ec28 488b4210 498bf9 498bf0 } // n = 5, score = 100 // 4156 | test byte ptr [eax + esi + 0x38], 0x40 // 4883ec28 | dec eax // 488b4210 | lea ecx, [0x1df3c] // 498bf9 | test eax, eax // 498bf0 | dec eax $sequence_5 = { 660f28d1 660f28c1 4c8d0d8b9f0000 f20f101d???????? f20f100d???????? } // n = 5, score = 100 // 660f28d1 | mov dword ptr [eax + 0x10], esi // 660f28c1 | dec eax // 4c8d0d8b9f0000 | lea ebp, [esp - 0x1070] // f20f101d???????? | // f20f100d???????? | $sequence_6 = { 488bcb 4a8d1441 482bf5 4c8d3436 } // n = 4, score = 100 // 488bcb | jb 0x524 // 4a8d1441 | dec eax // 482bf5 | cmp ecx, 0x27 // 4c8d3436 | ja 0x51e $sequence_7 = { 4833cc e8???????? 488b9c24a0110000 4881c470110000 5f } // n = 5, score = 100 // 4833cc | je 0x1c4 // e8???????? | // 488b9c24a0110000 | dec eax // 4881c470110000 | cmp dword ptr [ebx + 0x18], 8 // 5f | jb 0x128 $sequence_8 = { 8bce 894d30 8bc6 894538 ffc3 83fb3c 0f8c6cffffff } // n = 7, score = 100 // 8bce | mov dword ptr [esp + 0x48], 0xf // 894d30 | mov byte ptr [esp + 0x30], 0 // 8bc6 | dec ecx // 894538 | or ecx, 0xffffffff // ffc3 | inc ebp // 83fb3c | xor eax, eax // 0f8c6cffffff | test eax, eax $sequence_9 = { 488bce e8???????? eb55 4c896d68 48c745700f000000 } // n = 5, score = 100 // 488bce | dec eax // e8???????? | // eb55 | mov ecx, dword ptr [ecx] // 4c896d68 | dec eax // 48c745700f000000 | mov ecx, dword ptr [ecx] condition: 7 of them and filesize < 331776 }
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