SYMBOLCOMMON_NAMEaka. SYNONYMS
win.ccleaner_backdoor (Back to overview)

CCleaner Backdoor

aka: DIRTCLEANER
VTCollection    

According to CrowdStrike, this backdoor was discovered embedded in the legitimate, signed version of CCleaner 5.33, and thus constitutes a supply chain attack.

References
2021-10-27 ⋅ Mandiant ⋅ Corey Hildebrandt, Daniel Kapellmann Zafra, Ken Proska, Nathan Brubaker
Portable Executable File Infecting Malware Is Increasingly Found in OT Networks
CCleaner Backdoor Floxif neshta Ramnit Sality Virut
2021-10-20 ⋅ Twitter (@lampnout) ⋅ Lampros Noutsos
Persistence and Privilege Escalation on Windows via Print Processors
CCleaner Backdoor
2020-09-08 ⋅ PTSecurity ⋅ PTSecurity
ShadowPad: new activity from the Winnti group
CCleaner Backdoor Korlia ShadowPad TypeHash
2020-07-20 ⋅ Risky.biz ⋅ Daniel Gordon
What even is Winnti?
CCleaner Backdoor Ghost RAT PlugX ZXShell
2020-06-09 ⋅ Kaspersky Labs ⋅ Costin Raiu
Looking at Big Threats Using Code Similarity. Part 1
Penquin Turla CCleaner Backdoor EternalPetya Regin WannaCryptor XTunnel
2020-01-01 ⋅ Secureworks ⋅ SecureWorks
BRONZE ATLAS
Speculoos Winnti ACEHASH CCleaner Backdoor CHINACHOPPER Empire Downloader HTran MimiKatz PlugX Winnti APT41
2018-04-17 ⋅ Avast ⋅ Ondrej Vlcek
Recent findings from CCleaner APT investigation reveal that attackers entered the Piriform network via TeamViewer
CCleaner Backdoor
2018-03-08 ⋅ Avast ⋅ Threat Intelligence Team
New investigations into the CCleaner incident point to a possible third stage that had keylogger capacities
CCleaner Backdoor
2017-11-10 ⋅ CrowdStrike ⋅ Karan Sood
CCleaner Stage 2: In-Depth Analysis of the Payload
CCleaner Backdoor
2017-10-04 ⋅ CrowdStrike ⋅ Karan Sood
Protecting the Software Supply Chain: Deep Insights into the CCleaner Backdoor
CCleaner Backdoor
2017-10-02 ⋅ Intezer ⋅ Jay Rosenberg
Evidence Aurora Operation Still Active Part 2: More Ties Uncovered Between CCleaner Hack & Chinese Hackers
CCleaner Backdoor
2017-09-25 ⋅ Avast ⋅ Threat Intelligence Team
Additional information regarding the recent CCleaner APT security incident
CCleaner Backdoor
2017-09-21 ⋅ Avast ⋅ Threat Intelligence Team
Avast Threat Labs analysis of CCleaner incident
CCleaner Backdoor
2017-09-20 ⋅ Cisco Talos ⋅ Craig Williams, Earl Carter, Edmund Brumaghin, Matthew Molyett, Matthew Olney, Paul Rascagnères, Warren Mercer
CCleaner Command and Control Causes Concern
CCleaner Backdoor
2017-09-20 ⋅ Wired ⋅ Andy Greenberg
The CCleaner Malware Fiasco Targeted at Least 18 Specific Tech Firms
CCleaner Backdoor
2017-09-20 ⋅ Avast ⋅ Ondrej Vlcek, Vince Steckler
Progress on CCleaner Investigation
CCleaner Backdoor
2017-09-20 ⋅ Intezer ⋅ Jay Rosenberg
Evidence Aurora Operation Still Active: Supply Chain Attack Through CCleaner
CCleaner Backdoor
2017-09-19 ⋅ Twitter (@craiu) ⋅ Costin Raiu
Tweet on Shared Code between CCleaner and APT17 Missl backdoor
CCleaner Backdoor
2017-09-19 ⋅ Security Intelligence ⋅ Larry Loeb
Security Utility Abuses Supply Chain for a Malware Attack
CCleaner Backdoor
2017-09-18 ⋅ Morphisec ⋅ Michael Gorelik
Morphisec Discovers CCleaner Backdoor Saving Millions of Avast Users
CCleaner Backdoor
2017-09-18 ⋅ Cisco Talos ⋅ Craig Williams, Edmund Brumaghin, Matthew Molyett, Ross Gibb, Warren Mercer
CCleanup: A Vast Number of Machines at Risk
CCleaner Backdoor
Yara Rules
[TLP:WHITE] win_ccleaner_backdoor_auto (20260504 | Detects win.ccleaner_backdoor.)
rule win_ccleaner_backdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.ccleaner_backdoor."
        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.ccleaner_backdoor"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { ffd6 50 ff15???????? 8b3d???????? 59 }
            // n = 5, score = 200
            //   ffd6                 | call                esi
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b3d????????         |                     
            //   59                   | pop                 ecx

        $sequence_1 = { b900010000 5f c60000 40 49 }
            // n = 5, score = 100
            //   b900010000           | mov                 ecx, 0x100
            //   5f                   | pop                 edi
            //   c60000               | mov                 byte ptr [eax], 0
            //   40                   | inc                 eax
            //   49                   | dec                 ecx

        $sequence_2 = { 03c6 85c0 7f09 488b0a 488b01 ff5008 488b4b28 }
            // n = 7, score = 100
            //   03c6                 | mov                 esi, dword ptr [ebx + 0x40]
            //   85c0                 | inc                 ecx
            //   7f09                 | mov                 eax, esp
            //   488b0a               | add                 eax, eax
            //   488b01               | mov                 dword ptr [ebx + 0x40], eax
            //   ff5008               | mov                 esi, dword ptr [ebx + 0x40]
            //   488b4b28             | inc                 ecx

        $sequence_3 = { 0f8302020000 8bc3 2bc2 83f803 0f82f1010000 }
            // n = 5, score = 100
            //   0f8302020000         | add                 edx, ecx
            //   8bc3                 | sub                 dword ptr [esp + 0x50], ecx
            //   2bc2                 | mov                 ecx, dword ptr [esp + 0x10]
            //   83f803               | cmp                 esi, dword ptr [esp + 0x40]
            //   0f82f1010000         | add                 dword ptr [esp + 0x54], eax

        $sequence_4 = { 012e 33c0 5f 5e }
            // n = 4, score = 100
            //   012e                 | lea                 ecx, [ebx + 0x18]
            //   33c0                 | add                 eax, esi
            //   5f                   | dec                 eax
            //   5e                   | arpl                ax, dx

        $sequence_5 = { 013e 33c0 8b16 83c410 }
            // n = 4, score = 100
            //   013e                 | dec                 eax
            //   33c0                 | mov                 edx, dword ptr [ebx + 0x48]
            //   8b16                 | add                 eax, esi
            //   83c410               | test                eax, eax

        $sequence_6 = { 03c6 4863d0 4c8d0c12 4c8d4718 }
            // n = 4, score = 100
            //   03c6                 | sub                 esp, 0x20
            //   4863d0               | add                 esp, ecx
            //   4c8d0c12             | int3                
            //   4c8d4718             | dec                 eax

        $sequence_7 = { 48 03d5 49 83f902 760b 41 }
            // n = 6, score = 100
            //   48                   | add                 edx, ecx
            //   03d5                 | sub                 dword ptr [esp + 0x50], ecx
            //   49                   | mov                 ecx, dword ptr [esp + 0x10]
            //   83f902               | cmp                 esi, dword ptr [esp + 0x40]
            //   760b                 | jne                 0x1a
            //   41                   | add                 dword ptr [esp + 0x54], eax

        $sequence_8 = { 01cc cc 48895c2408 57 }
            // n = 4, score = 100
            //   01cc                 | sub                 edx, 0x18
            //   cc                   | or                  eax, 0xffffffff
            //   48895c2408           | lock xadd           dword ptr [edx + 0x10], eax
            //   57                   | add                 dword ptr [esi + 0xc], eax

        $sequence_9 = { 8d45f8 50 e8???????? 0fb645fb 83c414 }
            // n = 5, score = 100
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   50                   | push                eax
            //   e8????????           |                     
            //   0fb645fb             | movzx               eax, byte ptr [ebp - 5]
            //   83c414               | add                 esp, 0x14

        $sequence_10 = { 50 6a00 8d8500ffffff 6a10 50 68e0000000 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   6a00                 | push                0
            //   8d8500ffffff         | lea                 eax, [ebp - 0x100]
            //   6a10                 | push                0x10
            //   50                   | push                eax
            //   68e0000000           | push                0xe0

        $sequence_11 = { 03c7 4863c8 488d1c4b 493bdc }
            // n = 4, score = 100
            //   03c7                 | add                 eax, esi
            //   4863c8               | dec                 eax
            //   488d1c4b             | arpl                ax, dx
            //   493bdc               | dec                 esp

        $sequence_12 = { 6a02 ff15???????? 56 e8???????? 8d45f8 53 }
            // n = 6, score = 100
            //   6a02                 | push                2
            //   ff15????????         |                     
            //   56                   | push                esi
            //   e8????????           |                     
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   53                   | push                ebx

        $sequence_13 = { 50 8b07 83e804 50 }
            // n = 4, score = 100
            //   50                   | push                eax
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   83e804               | sub                 eax, 4
            //   50                   | push                eax

        $sequence_14 = { 01442418 03c8 8954242c 8b542470 }
            // n = 4, score = 100
            //   01442418             | dec                 eax
            //   03c8                 | lea                 ebx, [ebx + ecx*2]
            //   8954242c             | dec                 ecx
            //   8b542470             | cmp                 ebx, esp

        $sequence_15 = { 4c 03d5 48 63c8 4c 2bc9 4d }
            // n = 7, score = 100
            //   4c                   | mov                 eax, dword ptr [esp + 0x44]
            //   03d5                 | add                 dword ptr [esi + 0x1c], eax
            //   48                   | mov                 edx, dword ptr [esp + 0x24]
            //   63c8                 | test                edx, edx
            //   4c                   | je                  0xd
            //   2bc9                 | add                 dword ptr [esi + 0x1c], eax
            //   4d                   | mov                 edx, dword ptr [esp + 0x24]

        $sequence_16 = { 014c2464 40 89542418 89442430 }
            // n = 4, score = 100
            //   014c2464             | mov                 edx, dword ptr [esi]
            //   40                   | add                 esp, 0x10
            //   89542418             | mov                 ecx, dword ptr [esi + 8]
            //   89442430             | inc                 eax

        $sequence_17 = { 01461c 8b542424 85d2 7405 }
            // n = 4, score = 100
            //   01461c               | add                 eax, 0x800
            //   8b542424             | cmp                 ecx, eax
            //   85d2                 | jae                 0x28
            //   7405                 | mov                 word ptr [ecx + 4], 0xa00

        $sequence_18 = { 01442454 03d1 294c2450 8b4c2410 }
            // n = 4, score = 100
            //   01442454             | pop                 ebp
            //   03d1                 | pop                 ebx
            //   294c2450             | add                 dword ptr [esi], ebp
            //   8b4c2410             | xor                 eax, eax

        $sequence_19 = { 01442424 eb30 8b4508 897518 }
            // n = 4, score = 100
            //   01442424             | test                ebp, ebp
            //   eb30                 | jle                 0x1f1
            //   8b4508               | add                 ebp, edi
            //   897518               | dec                 edx

        $sequence_20 = { 00cc cc 4057 4883ec50 }
            // n = 4, score = 100
            //   00cc                 | add                 ah, cl
            //   cc                   | int3                
            //   4057                 | inc                 eax
            //   4883ec50             | push                edi

        $sequence_21 = { ebc2 83e10f 8b348d68c60210 23751c d36d1c }
            // n = 5, score = 100
            //   ebc2                 | add                 edx, ecx
            //   83e10f               | sub                 dword ptr [esp + 0x50], ecx
            //   8b348d68c60210       | mov                 ecx, dword ptr [esp + 0x10]
            //   23751c               | cmp                 esi, dword ptr [esp + 0x40]
            //   d36d1c               | jne                 0x1a

        $sequence_22 = { 01460c 488b3f 493bfc 0f8554ffffff }
            // n = 4, score = 100
            //   01460c               | dec                 eax
            //   488b3f               | sub                 esp, 0x28
            //   493bfc               | dec                 eax
            //   0f8554ffffff         | mov                 edx, dword ptr [ecx]

        $sequence_23 = { 8802 8a4701 42 47 }
            // n = 4, score = 100
            //   8802                 | mov                 ecx, dword ptr [esi + 0x1c]
            //   8a4701               | mov                 dword ptr [edx], ecx
            //   42                   | add                 dword ptr [esi + 0x1c], eax
            //   47                   | mov                 edx, dword ptr [esp + 0x24]

        $sequence_24 = { 46 83fe3c 7cd0 33c0 5e c9 c3 }
            // n = 7, score = 100
            //   46                   | test                edx, edx
            //   83fe3c               | je                  0xd
            //   7cd0                 | mov                 ecx, dword ptr [esi + 0x1c]
            //   33c0                 | add                 dword ptr [esi + 0x1c], eax
            //   5e                   | mov                 edx, dword ptr [esp + 0x24]
            //   c9                   | test                edx, edx
            //   c3                   | je                  9

        $sequence_25 = { 03c0 894340 8b7340 418bc4 }
            // n = 4, score = 100
            //   03c0                 | xor                 eax, eax
            //   894340               | jmp                 0x15
            //   8b7340               | add                 dword ptr [esi + 0xc], eax
            //   418bc4               | dec                 eax

        $sequence_26 = { 8b4508 c70609000000 c7471830b30210 894620 }
            // n = 4, score = 100
            //   8b4508               | add                 edx, ecx
            //   c70609000000         | sub                 dword ptr [esp + 0x50], ecx
            //   c7471830b30210       | mov                 ecx, dword ptr [esp + 0x10]
            //   894620               | add                 dword ptr [esp + 0x54], eax

        $sequence_27 = { 00cc cc 4883ec28 488b11 }
            // n = 4, score = 100
            //   00cc                 | dec                 esp
            //   cc                   | mov                 edx, ecx
            //   4883ec28             | add                 ah, cl
            //   488b11               | int3                

        $sequence_28 = { 83c0fc 8d4f08 53 50 51 }
            // n = 5, score = 100
            //   83c0fc               | add                 eax, -4
            //   8d4f08               | lea                 ecx, [edi + 8]
            //   53                   | push                ebx
            //   50                   | push                eax
            //   51                   | push                ecx

        $sequence_29 = { 013d???????? 8b04b5d8970210 0500080000 3bc8 }
            // n = 4, score = 100
            //   013d????????         |                     
            //   8b04b5d8970210       | add                 eax, esi
            //   0500080000           | test                eax, eax
            //   3bc8                 | jg                  0xd

        $sequence_30 = { ff75f8 ff15???????? 85c0 7518 8d856cfdffff }
            // n = 5, score = 100
            //   ff75f8               | push                dword ptr [ebp - 8]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7518                 | jne                 0x1a
            //   8d856cfdffff         | lea                 eax, [ebp - 0x294]

    condition:
        7 of them and filesize < 377856
}
[TLP:WHITE] win_ccleaner_backdoor_w0   (20180301 | No description)
rule win_ccleaner_backdoor_w0 {
    meta:
        author = "Florian Roth"
        reference = "https://goo.gl/puVc9q"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.ccleaner_backdoor"
        malpedia_version = "20180301"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $s1 = "\\spool\\prtprocs\\w32x86\\localspl.dll" fullword ascii
        $s2 = "\\spool\\prtprocs\\x64\\localspl.dll" fullword ascii
        $s3 = "\\msvcrt.dll" fullword ascii
        $s4 = "\\TSMSISrv.dll" fullword ascii
    condition:
        all of them
}
[TLP:WHITE] win_ccleaner_backdoor_w1   (20180301 | No description)
import "pe"

rule win_ccleaner_backdoor_w1 {
    meta:
        author = "Florian Roth"
        reference = "https://goo.gl/puVc9q"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.ccleaner_backdoor"
        malpedia_version = "20180301"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $s1 = "Copyright (c) 2007 - 2011 Symantec Corporation" fullword wide
        $s2 = "\\\\.\\SYMEFA" fullword wide
    condition:
        all of them and pe.number_of_signatures == 0
}
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