SYMBOLCOMMON_NAMEaka. SYNONYMS
win.roseam (Back to overview)

Roseam

aka: PisLoader

Actor(s): Wekby


There is no description at this point.

References
2016-05-24Palo Alto Networks Unit 42Josh Grunzweig, Mike Scott, Bryan Lee
@online{grunzweig:20160524:new:d1cd669, author = {Josh Grunzweig and Mike Scott and Bryan Lee}, title = {{New Wekby Attacks Use DNS Requests As Command and Control Mechanism}}, date = {2016-05-24}, organization = {Palo Alto Networks Unit 42}, url = {http://researchcenter.paloaltonetworks.com/2016/05/unit42-new-wekby-attacks-use-dns-requests-as-command-and-control-mechanism/}, language = {English}, urldate = {2019-12-20} } New Wekby Attacks Use DNS Requests As Command and Control Mechanism
Roseam
Yara Rules
[TLP:WHITE] win_roseam_auto (20220808 | Detects win.roseam.)
rule win_roseam_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.roseam."
        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.roseam"
        malpedia_rule_date = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 5d 68???????? 55 8bec 9c 6845061504 6864110404 }
            // n = 7, score = 100
            //   5d                   | pop                 ebp
            //   68????????           |                     
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   9c                   | pushfd              
            //   6845061504           | push                0x4150645
            //   6864110404           | push                0x4041164

        $sequence_1 = { 53 56 57 50 ff15???????? 8b5d08 }
            // n = 6, score = 100
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b5d08               | mov                 ebx, dword ptr [ebp + 8]

        $sequence_2 = { 6a01 668906 ff15???????? 66894602 68???????? 68???????? }
            // n = 6, score = 100
            //   6a01                 | push                1
            //   668906               | mov                 word ptr [esi], ax
            //   ff15????????         |                     
            //   66894602             | mov                 word ptr [esi + 2], ax
            //   68????????           |                     
            //   68????????           |                     

        $sequence_3 = { f2ae f7d1 49 894dec 8d0489 99 }
            // n = 6, score = 100
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]
            //   f7d1                 | not                 ecx
            //   49                   | dec                 ecx
            //   894dec               | mov                 dword ptr [ebp - 0x14], ecx
            //   8d0489               | lea                 eax, [ecx + ecx*4]
            //   99                   | cdq                 

        $sequence_4 = { 6841061504 6869110404 64a100000000 50 64892500000000 }
            // n = 5, score = 100
            //   6841061504           | push                0x4150641
            //   6869110404           | push                0x4041169
            //   64a100000000         | mov                 eax, dword ptr fs:[0]
            //   50                   | push                eax
            //   64892500000000       | mov                 dword ptr fs:[0], esp

        $sequence_5 = { 80c241 8855ff 68???????? 55 }
            // n = 4, score = 100
            //   80c241               | add                 dl, 0x41
            //   8855ff               | mov                 byte ptr [ebp - 1], dl
            //   68????????           |                     
            //   55                   | push                ebp

        $sequence_6 = { 52 50 e8???????? 8b8d7cffffff 83c40c }
            // n = 5, score = 100
            //   52                   | push                edx
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b8d7cffffff         | mov                 ecx, dword ptr [ebp - 0x84]
            //   83c40c               | add                 esp, 0xc

        $sequence_7 = { 33c0 8dbd76e8ffff 6689b574e8ffff f3ab 8d9574ecffff 52 66ab }
            // n = 7, score = 100
            //   33c0                 | xor                 eax, eax
            //   8dbd76e8ffff         | lea                 edi, [ebp - 0x178a]
            //   6689b574e8ffff       | mov                 word ptr [ebp - 0x178c], si
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   8d9574ecffff         | lea                 edx, [ebp - 0x138c]
            //   52                   | push                edx
            //   66ab                 | stosw               word ptr es:[edi], ax

        $sequence_8 = { 80c120 888800904100 eb1f 83f861 7213 }
            // n = 5, score = 100
            //   80c120               | add                 cl, 0x20
            //   888800904100         | mov                 byte ptr [eax + 0x419000], cl
            //   eb1f                 | jmp                 0x21
            //   83f861               | cmp                 eax, 0x61
            //   7213                 | jb                  0x15

        $sequence_9 = { 6a01 ff15???????? 85c0 0f8529020000 68???????? 68???????? 50 }
            // n = 7, score = 100
            //   6a01                 | push                1
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f8529020000         | jne                 0x22f
            //   68????????           |                     
            //   68????????           |                     
            //   50                   | push                eax

    condition:
        7 of them and filesize < 221184
}
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