According to CISA, SUPERNOVA is a malicious webshell backdoor that allows a remote operator to dynamically inject C# source code into a web portal to subsequently inject code. APT actors use SUPERNOVA to perform reconnaissance, conduct domain mapping, and steal sensitive information and credentials.
rule win_supernova_auto {
meta:
author = "Felix Bilstein - yara-signator at cocacoding dot com"
date = "2026-01-05"
version = "1"
description = "Detects win.supernova."
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.supernova"
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 = { 1107 17 91 1f50 3339 1107 }
// n = 6, score = 100
// 1107 | jo 0x3b7
// 17 | sub dword ptr [eax], eax
// 91 | add byte ptr [edx], cl
// 1f50 | and eax, 0x286f
// 3339 | or dh, byte ptr [edx - 0x4f]
// 1107 | add dword ptr [eax], eax
$sequence_1 = { 1308 03 6f0b00000a 6f1c00000a 1107 16 }
// n = 6, score = 100
// 1308 | or dword ptr [eax], eax
// 03 | add byte ptr [edx], cl
// 6f0b00000a | pop ss
// 6f1c00000a | lea edx, [ebx]
// 1107 | add byte ptr [eax], al
// 16 | add dword ptr [0x22772], esp
$sequence_2 = { 26 25 6f2800000a 72b1010070 }
// n = 4, score = 100
// 26 | add byte ptr [ebx], dh
// 25 | or al, 0x72
// 6f2800000a | int 0
// 72b1010070 | add byte ptr [eax + 0x13], dh
$sequence_3 = { 19 91 1f47 3329 }
// n = 4, score = 100
// 19 | and byte ptr [ecx + 0x33000000], cl
// 91 | inc ecx
// 1f47 | push ss
// 3329 | xchg eax, ecx
$sequence_4 = { 3341 1107 17 91 1f50 3339 }
// n = 6, score = 100
// 3341 | or dword ptr [edi + 0x22], ebp
// 1107 | add byte ptr [eax], al
// 17 | or bl, dh
// 91 | add byte ptr [esi], dl
// 1f50 | adc dword ptr [edi], eax
// 3339 | mov gs, word ptr [ecx + 0x6f]
$sequence_5 = { 1f0a 9d 6f0a00000a 1304 03 6f0b00000a }
// n = 6, score = 100
// 1f0a | and dword ptr [eax], eax
// 9d | add byte ptr [edx], cl
// 6f0a00000a | fiadd word ptr [esi + 0x13]
// 1304 | or dword ptr [ebx], eax
// 03 | outsd dx, dword ptr [esi]
// 6f0b00000a | or eax, dword ptr [eax]
$sequence_6 = { de00 03 6f0800000a 6f0e00000a }
// n = 4, score = 100
// de00 | or ch, byte ptr [edi + 0x2d]
// 03 | add byte ptr [eax], al
// 6f0800000a | or ch, byte ptr [edi + 0x35]
// 6f0e00000a | add byte ptr [eax], al
$sequence_7 = { 3309 72e3000070 1308 2b5a 1107 }
// n = 5, score = 100
// 3309 | adc dword ptr [edi], eax
// 72e3000070 | pop ss
// 1308 | outsd dx, dword ptr [esi]
// 2b5a | pop ds
// 1107 | add byte ptr [eax], al
$sequence_8 = { 16 91 2089000000 3341 }
// n = 4, score = 100
// 16 | adc eax, dword ptr [esi]
// 91 | sub eax, dword ptr [edi]
// 2089000000 | sub byte ptr [0x130a0000], dl
// 3341 | push es
$sequence_9 = { 7e01000004 7211010070 1109 6f2200000a de00 03 6f0b00000a }
// n = 7, score = 100
// 7e01000004 | adc al, byte ptr [eax]
// 7211010070 | add byte ptr [edx], cl
// 1109 | sub eax, 0x6f051128
// 6f2200000a | adc dword ptr [eax], eax
// de00 | add byte ptr [edx], cl
// 03 | jae 0x33
// 6f0b00000a | add byte ptr [eax], al
condition:
7 of them and filesize < 50176
}
[TLP:WHITE] win_supernova_w0 (20201216 | This rule is looking for specific strings related to SUPERNOVA. SUPERNOVA is a .NET web shell backdoor masquerading as a legitimate SolarWinds web service handler. SUPERNOVA inspects and responds to HTTP requests with the appropriate HTTP query strings, Cookies, and/or HTML form values (e.g. named codes, class, method, and args).)
// Copyright 2020 by FireEye, Inc.
// You may not use this file except in compliance with the license. The license should have been received with this file. You may obtain a copy of the license at:
// https://github.com/fireeye/sunburst_countermeasures/blob/main/LICENSE.txt
rule win_supernova_w0 {
meta:
author = "FireEye"
description = "This rule is looking for specific strings related to SUPERNOVA. SUPERNOVA is a .NET web shell backdoor masquerading as a legitimate SolarWinds web service handler. SUPERNOVA inspects and responds to HTTP requests with the appropriate HTTP query strings, Cookies, and/or HTML form values (e.g. named codes, class, method, and args)."
malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.supernova"
malpedia_version = "20201216"
malpedia_license = ""
malpedia_sharing = "TLP:WHITE"
malpedia_license = ""
strings:
$dynamic = "DynamicRun"
$solar = "Solarwinds" nocase
$string1 = "codes"
$string2 = "clazz"
$string3 = "method"
$string4 = "args"
condition:
uint16(0) == 0x5a4d
and
uint32(uint32(0x3C)) == 0x00004550
and
filesize < 10KB
and
3 of ($string*)
and
$dynamic
and
$solar
}
[TLP:WHITE] win_supernova_w1 (20201216 | SUPERNOVA is a .NET web shell backdoor masquerading as a legitimate SolarWinds web service handler. SUPERNOVA inspects and responds to HTTP requests with the appropriate HTTP query strings, Cookies, and/or HTML form values (e.g. named codes, class, method, and args). This rule is looking for specific strings and attributes related to SUPERNOVA.)
// Copyright 2020 by FireEye, Inc.
// You may not use this file except in compliance with the license. The license should have been received with this file. You may obtain a copy of the license at:
// https://github.com/fireeye/sunburst_countermeasures/blob/main/LICENSE.txt
import "pe"
rule win_supernova_w1 {
meta:
author = "FireEye"
description = "SUPERNOVA is a .NET web shell backdoor masquerading as a legitimate SolarWinds web service handler. SUPERNOVA inspects and responds to HTTP requests with the appropriate HTTP query strings, Cookies, and/or HTML form values (e.g. named codes, class, method, and args). This rule is looking for specific strings and attributes related to SUPERNOVA."
malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.supernova"
malpedia_version = "20201216"
malpedia_license = ""
malpedia_sharing = "TLP:WHITE"
malpedia_license = ""
strings:
$compile1 = "CompileAssemblyFromSource"
$compile2 = "CreateCompiler"
$context = "ProcessRequest"
$httpmodule = "IHttpHandler" ascii
$string1 = "clazz"
$string2 = "//NetPerfMon//images//NoLogo.gif" wide
$string3 = "SolarWinds" ascii nocase wide
condition:
uint16(0) == 0x5a4d
and
uint32(uint32(0x3C)) == 0x00004550
and
filesize < 10KB
and
pe.imports("mscoree.dll","_CorDllMain")
and
$httpmodule
and
$context
and
all of ($compile*)
and
all of ($string*)
}
