SYMBOLCOMMON_NAMEaka. SYNONYMS
win.orcarat (Back to overview)

OrcaRAT


OrcaRAT is a Backdoor that targets the Windows platform. It has been reported that a variant of this malware has been used in a targeted attack. It contacts a remote server, sending system information. Moreover, it receives control commands to execute shell commands, and download/upload a file, among other actions.

References
2020SecureworksSecureWorks
@online{secureworks:2020:bronze:dcdc02a, author = {SecureWorks}, title = {{BRONZE FLEETWOOD}}, date = {2020}, organization = {Secureworks}, url = {https://www.secureworks.com/research/threat-profiles/bronze-fleetwood}, language = {English}, urldate = {2020-05-23} } BRONZE FLEETWOOD
Binanen Ghost RAT OrcaRAT APT5
2014-10-20PWCDan Kelly, Tom Lancaster
@online{kelly:20141020:orcarat:236c19f, author = {Dan Kelly and Tom Lancaster}, title = {{OrcaRAT - A whale of a tale}}, date = {2014-10-20}, organization = {PWC}, url = {http://pwc.blogs.com/cyber_security_updates/2014/10/orcarat-a-whale-of-a-tale.html}, language = {English}, urldate = {2019-11-24} } OrcaRAT - A whale of a tale
OrcaRAT
Yara Rules
[TLP:WHITE] win_orcarat_auto (20201023 | autogenerated rule brought to you by yara-signator)
rule win_orcarat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-12-22"
        version = "1"
        description = "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.orcarat"
        malpedia_rule_date = "20201222"
        malpedia_hash = "30354d830a29f0fbd3714d93d94dea941d77a130"
        malpedia_version = "20201023"
        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 = { 3b05???????? 733d 8bc8 8bd0 c1f905 83e21f 8b0c8dc0c74000 }
            // n = 7, score = 200
            //   3b05????????         |                     
            //   733d                 | jae                 0x3f
            //   8bc8                 | mov                 ecx, eax
            //   8bd0                 | mov                 edx, eax
            //   c1f905               | sar                 ecx, 5
            //   83e21f               | and                 edx, 0x1f
            //   8b0c8dc0c74000       | mov                 ecx, dword ptr [ecx*4 + 0x40c7c0]

        $sequence_1 = { 751a 3844240d 7514 807c240e3f 750d b801000000 5e }
            // n = 7, score = 200
            //   751a                 | jne                 0x1c
            //   3844240d             | cmp                 byte ptr [esp + 0xd], al
            //   7514                 | jne                 0x16
            //   807c240e3f           | cmp                 byte ptr [esp + 0xe], 0x3f
            //   750d                 | jne                 0xf
            //   b801000000           | mov                 eax, 1
            //   5e                   | pop                 esi

        $sequence_2 = { ff24856c254000 8d44240e 8bce 50 e8???????? 5f 5e }
            // n = 7, score = 200
            //   ff24856c254000       | jmp                 dword ptr [eax*4 + 0x40256c]
            //   8d44240e             | lea                 eax, [esp + 0xe]
            //   8bce                 | mov                 ecx, esi
            //   50                   | push                eax
            //   e8????????           |                     
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_3 = { be04010000 52 50 89742410 ff15???????? 85c0 }
            // n = 6, score = 200
            //   be04010000           | mov                 esi, 0x104
            //   52                   | push                edx
            //   50                   | push                eax
            //   89742410             | mov                 dword ptr [esp + 0x10], esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax

        $sequence_4 = { 2bf9 8d94241c010000 8bf7 8bd9 }
            // n = 4, score = 200
            //   2bf9                 | sub                 edi, ecx
            //   8d94241c010000       | lea                 edx, [esp + 0x11c]
            //   8bf7                 | mov                 esi, edi
            //   8bd9                 | mov                 ebx, ecx

        $sequence_5 = { 33db 837d0000 762f 8d442410 c744241000000000 50 }
            // n = 6, score = 200
            //   33db                 | xor                 ebx, ebx
            //   837d0000             | cmp                 dword ptr [ebp], 0
            //   762f                 | jbe                 0x31
            //   8d442410             | lea                 eax, [esp + 0x10]
            //   c744241000000000     | mov                 dword ptr [esp + 0x10], 0
            //   50                   | push                eax

        $sequence_6 = { 51 52 6813000020 56 c744242801000000 }
            // n = 5, score = 200
            //   51                   | push                ecx
            //   52                   | push                edx
            //   6813000020           | push                0x20000013
            //   56                   | push                esi
            //   c744242801000000     | mov                 dword ptr [esp + 0x28], 1

        $sequence_7 = { 6801680000 50 ff15???????? 8bf0 }
            // n = 4, score = 200
            //   6801680000           | push                0x6801
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_8 = { 894c2418 ff15???????? 50 e8???????? 8d7c2424 83c9ff 33c0 }
            // n = 7, score = 200
            //   894c2418             | mov                 dword ptr [esp + 0x18], ecx
            //   ff15????????         |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   8d7c2424             | lea                 edi, [esp + 0x24]
            //   83c9ff               | or                  ecx, 0xffffffff
            //   33c0                 | xor                 eax, eax

        $sequence_9 = { e8???????? 8b542410 8d44240c 8d8c2418010000 50 51 8d842430110000 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8b542410             | mov                 edx, dword ptr [esp + 0x10]
            //   8d44240c             | lea                 eax, [esp + 0xc]
            //   8d8c2418010000       | lea                 ecx, [esp + 0x118]
            //   50                   | push                eax
            //   51                   | push                ecx
            //   8d842430110000       | lea                 eax, [esp + 0x1130]

    condition:
        7 of them and filesize < 114688
}
[TLP:WHITE] win_orcarat_w0   (20180930 | No description)
rule win_orcarat_w0 {
    meta:  
        author = "PwC Cyber Threat Operations :: @tlansec"
        info = "removed MZ@0 and filesize to aid memory scanning"
        sha1 = "253a704acd7952677c70e0c2d787791b8359efe2c92a5e77acea028393a85613"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.orcarat"
        malpedia_version = "20180930"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $apptype1="application/x-ms-application"
        $apptype2="application/x-ms-xbap"
        $apptype3="application/vnd.ms-xpsdocument"
        $apptype4="application/xaml+xml"
        $apptype5="application/x-shockwave-flash"
        $apptype6="image/pjpeg"
        $err1="Set return time error =   %d!"
        $err2="Set return time   success!"
        $err3="Quit success!"

    condition:
        all of ($apptype*) and 1 of ($err*)
}
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