SYMBOLCOMMON_NAMEaka. SYNONYMS
win.darkcloud (Back to overview)

DarkCloud Stealer


Stealer is written in Visual Basic.

References
2023-05-23AhnLabASEC
@online{asec:20230523:darkcloud:cbd48ff, author = {ASEC}, title = {{DarkCloud Infostealer Being Distributed via Spam Emails}}, date = {2023-05-23}, organization = {AhnLab}, url = {https://asec.ahnlab.com/en/53128/}, language = {English}, urldate = {2023-08-07} } DarkCloud Infostealer Being Distributed via Spam Emails
DarkCloud Stealer
2022-10-01Malware Hellc3rb3ru5d3d53c
@online{c3rb3ru5d3d53c:20221001:darkcloud:8c1f80f, author = {c3rb3ru5d3d53c}, title = {{DarkCloud Stealer Triage}}, date = {2022-10-01}, organization = {Malware Hell}, url = {https://c3rb3ru5d3d53c.github.io/malware-blog/darkcloud-stealer/}, language = {English}, urldate = {2022-11-25} } DarkCloud Stealer Triage
DarkCloud Stealer
Yara Rules
[TLP:WHITE] win_darkcloud_auto (20230715 | Detects win.darkcloud.)
rule win_darkcloud_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.darkcloud."
        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.darkcloud"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 8b45b8 8b8df8feffff 3b4810 730c c785c0fdffff00000000 eb0c ff15???????? }
            // n = 7, score = 100
            //   8b45b8               | mov                 eax, dword ptr [ebp - 0x48]
            //   8b8df8feffff         | mov                 ecx, dword ptr [ebp - 0x108]
            //   3b4810               | cmp                 ecx, dword ptr [eax + 0x10]
            //   730c                 | jae                 0xe
            //   c785c0fdffff00000000     | mov    dword ptr [ebp - 0x240], 0
            //   eb0c                 | jmp                 0xe
            //   ff15????????         |                     

        $sequence_1 = { 8b55dc 66833a01 7547 0fbf45d0 8b4ddc 2b4114 8985f8feffff }
            // n = 7, score = 100
            //   8b55dc               | mov                 edx, dword ptr [ebp - 0x24]
            //   66833a01             | cmp                 word ptr [edx], 1
            //   7547                 | jne                 0x49
            //   0fbf45d0             | movsx               eax, word ptr [ebp - 0x30]
            //   8b4ddc               | mov                 ecx, dword ptr [ebp - 0x24]
            //   2b4114               | sub                 eax, dword ptr [ecx + 0x14]
            //   8985f8feffff         | mov                 dword ptr [ebp - 0x108], eax

        $sequence_2 = { 0fbf8d44ffffff 85c9 7414 c745fc34000000 8b15???????? 52 ff15???????? }
            // n = 7, score = 100
            //   0fbf8d44ffffff       | movsx               ecx, word ptr [ebp - 0xbc]
            //   85c9                 | test                ecx, ecx
            //   7414                 | je                  0x16
            //   c745fc34000000       | mov                 dword ptr [ebp - 4], 0x34
            //   8b15????????         |                     
            //   52                   | push                edx
            //   ff15????????         |                     

        $sequence_3 = { 730c c7857cfcffff00000000 eb0c ff15???????? 89857cfcffff 8b8dd8fdffff 6bc90c }
            // n = 7, score = 100
            //   730c                 | jae                 0xe
            //   c7857cfcffff00000000     | mov    dword ptr [ebp - 0x384], 0
            //   eb0c                 | jmp                 0xe
            //   ff15????????         |                     
            //   89857cfcffff         | mov                 dword ptr [ebp - 0x384], eax
            //   8b8dd8fdffff         | mov                 ecx, dword ptr [ebp - 0x228]
            //   6bc90c               | imul                ecx, ecx, 0xc

        $sequence_4 = { 51 52 e8???????? 8bf0 ffd7 3bf3 0f8cbe020000 }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   52                   | push                edx
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax
            //   ffd7                 | call                edi
            //   3bf3                 | cmp                 esi, ebx
            //   0f8cbe020000         | jl                  0x2c4

        $sequence_5 = { 68???????? 8b9584feffff 52 8b8580feffff 50 ff15???????? 898520fdffff }
            // n = 7, score = 100
            //   68????????           |                     
            //   8b9584feffff         | mov                 edx, dword ptr [ebp - 0x17c]
            //   52                   | push                edx
            //   8b8580feffff         | mov                 eax, dword ptr [ebp - 0x180]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   898520fdffff         | mov                 dword ptr [ebp - 0x2e0], eax

        $sequence_6 = { 8d4d94 ffd3 8b45e4 6a00 50 e8???????? 8d8d7cffffff }
            // n = 7, score = 100
            //   8d4d94               | lea                 ecx, [ebp - 0x6c]
            //   ffd3                 | call                ebx
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   e8????????           |                     
            //   8d8d7cffffff         | lea                 ecx, [ebp - 0x84]

        $sequence_7 = { ffd6 8b4de4 50 51 ff9394000000 85c0 }
            // n = 6, score = 100
            //   ffd6                 | call                esi
            //   8b4de4               | mov                 ecx, dword ptr [ebp - 0x1c]
            //   50                   | push                eax
            //   51                   | push                ecx
            //   ff9394000000         | call                dword ptr [ebx + 0x94]
            //   85c0                 | test                eax, eax

        $sequence_8 = { ff15???????? ba???????? 8d4dcc ff15???????? 8b55c8 89951cffffff c745c800000000 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   ba????????           |                     
            //   8d4dcc               | lea                 ecx, [ebp - 0x34]
            //   ff15????????         |                     
            //   8b55c8               | mov                 edx, dword ptr [ebp - 0x38]
            //   89951cffffff         | mov                 dword ptr [ebp - 0xe4], edx
            //   c745c800000000       | mov                 dword ptr [ebp - 0x38], 0

        $sequence_9 = { c745fc18000000 ba???????? 8d4d98 ff15???????? 8d5598 52 e8???????? }
            // n = 7, score = 100
            //   c745fc18000000       | mov                 dword ptr [ebp - 4], 0x18
            //   ba????????           |                     
            //   8d4d98               | lea                 ecx, [ebp - 0x68]
            //   ff15????????         |                     
            //   8d5598               | lea                 edx, [ebp - 0x68]
            //   52                   | push                edx
            //   e8????????           |                     

    condition:
        7 of them and filesize < 622592
}
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