SYMBOLCOMMON_NAMEaka. SYNONYMS
win.session_manager (Back to overview)

SessionManager

Actor(s): Gelsemium


A malicious IIS module that allows up/download of files, remote command execution, and using the compromised server as a hop into the network behind.

References
2022-06-30KasperskyPierre Delcher
@online{delcher:20220630:sessionmanager:f171df2, author = {Pierre Delcher}, title = {{The SessionManager IIS backdoor: a possibly overlooked GELSEMIUM artefact}}, date = {2022-06-30}, organization = {Kaspersky}, url = {https://securelist.com/the-sessionmanager-iis-backdoor/106868/}, language = {English}, urldate = {2022-07-05} } The SessionManager IIS backdoor: a possibly overlooked GELSEMIUM artefact
MimiKatz Owlproxy SessionManager
Yara Rules
[TLP:WHITE] win_session_manager_auto (20230125 | Detects win.session_manager.)
rule win_session_manager_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.session_manager."
        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.session_manager"
        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 = { c60000 4533c0 488d1530dc0100 488bcb e8???????? 90 488b45ef }
            // n = 7, score = 100
            //   c60000               | dec                 eax
            //   4533c0               | mov                 dword ptr [esp + 0x1460], eax
            //   488d1530dc0100       | dec                 esp
            //   488bcb               | arpl                dx, dx
            //   e8????????           |                     
            //   90                   | dec                 eax
            //   488b45ef             | mov                 ebx, ecx

        $sequence_1 = { 488d4de0 e8???????? 488bd8 498b16 498bce ff5220 488bd0 }
            // n = 7, score = 100
            //   488d4de0             | dec                 esp
            //   e8????????           |                     
            //   488bd8               | mov                 dword ptr [eax + 0x1878], edi
            //   498b16               | dec                 esp
            //   498bce               | mov                 dword ptr [eax + 0x1880], edi
            //   ff5220               | dec                 esp
            //   488bd0               | mov                 dword ptr [eax + 0x1888], edi

        $sequence_2 = { 44882b eb7b 488b9540070000 4c8d05975d0000 498bce e8???????? }
            // n = 6, score = 100
            //   44882b               | mov                 dword ptr [eax + 0x1150], edi
            //   eb7b                 | dec                 esp
            //   488b9540070000       | mov                 dword ptr [eax + 0x1158], edi
            //   4c8d05975d0000       | dec                 esp
            //   498bce               | mov                 dword ptr [eax + 0x1238], edi
            //   e8????????           |                     

        $sequence_3 = { 41ff9280000000 ba09000000 498bcd e8???????? 4c8bf8 4885c0 }
            // n = 6, score = 100
            //   41ff9280000000       | mov                 dword ptr [eax + 0x940], edi
            //   ba09000000           | dec                 esp
            //   498bcd               | mov                 dword ptr [eax + 0x948], edi
            //   e8????????           |                     
            //   4c8bf8               | dec                 esp
            //   4885c0               | mov                 dword ptr [eax + 0x950], edi

        $sequence_4 = { 4883ec20 488bd9 488bc2 488d0d3d450100 }
            // n = 4, score = 100
            //   4883ec20             | dec                 eax
            //   488bd9               | lea                 ecx, [ebp - 0x29]
            //   488bc2               | dec                 eax
            //   488d0d3d450100       | mov                 edi, eax

        $sequence_5 = { 488d154a2e0100 488bc1 83e13f 48c1f806 }
            // n = 4, score = 100
            //   488d154a2e0100       | mov                 eax, dword ptr [ebx + 0x18]
            //   488bc1               | dec                 eax
            //   83e13f               | cmp                 eax, 0x10
            //   48c1f806             | jb                  0x901

        $sequence_6 = { eb5f 8bce e8???????? 83cbff 488d0586790100 }
            // n = 5, score = 100
            //   eb5f                 | dec                 esp
            //   8bce                 | mov                 dword ptr [eax + 0x2230], edi
            //   e8????????           |                     
            //   83cbff               | dec                 esp
            //   488d0586790100       | mov                 dword ptr [eax + 0x2310], edi

        $sequence_7 = { 33db 488d3d055c0100 488b0c3b 4885c9 740a }
            // n = 5, score = 100
            //   33db                 | dec                 esp
            //   488d3d055c0100       | mov                 dword ptr [eax + 0x2488], edi
            //   488b0c3b             | dec                 esp
            //   4885c9               | mov                 dword ptr [eax + 0x2490], edi
            //   740a                 | dec                 esp

        $sequence_8 = { 4c89b820010000 4c89b828010000 4c89b830010000 4c89b838010000 4c89b840010000 4c89b848010000 }
            // n = 6, score = 100
            //   4c89b820010000       | dec                 esp
            //   4c89b828010000       | mov                 dword ptr [eax + 0x25c8], edi
            //   4c89b830010000       | dec                 esp
            //   4c89b838010000       | mov                 dword ptr [eax + 0x25d0], edi
            //   4c89b840010000       | dec                 esp
            //   4c89b848010000       | mov                 dword ptr [eax + 0x25d8], edi

        $sequence_9 = { 4c89b818230000 4c89b820230000 4c89b828230000 4c89b830230000 4c89b838230000 }
            // n = 5, score = 100
            //   4c89b818230000       | dec                 eax
            //   4c89b820230000       | lea                 ecx, [0xf6fe]
            //   4c89b828230000       | mov                 dword ptr [ebx + 0x50], 6
            //   4c89b830230000       | dec                 eax
            //   4c89b838230000       | mov                 dword ptr [ebx + 0x48], ecx

    condition:
        7 of them and filesize < 372736
}
Download all Yara Rules