Analysis Report

MAR-10376640-2.v1 – CaddyWiper

Last Revised
Alert Code


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CISA received one unique file for analysis. This file is a malicious 32-bit Windows Portable Executable (PE). During runtime, this malware attempts to overwrite the victim user's files with null bytes. The malware also attempts to overwrite the Master Boot Record of attached drives with null bytes, thereby corrupting them and rendering it impossible for the victim to access the victim's stored data.

For a downloadable copy of IOCs, see: MAR-10376640-2.v1.stix.

Submitted Files (1)

a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea (a294620543334a721a2ae8eaaf9680...)





Name a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea
Size 9216 bytes
Type PE32 executable (GUI) Intel 80386, for MS Windows
MD5 42e52b8daf63e6e26c3aa91e7e971492
SHA1 98b3fb74b3e8b3f9b05a82473551c5a77b576d54
SHA256 a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea
SHA512 b21039ad67e07a77bbcfe73a89afd22c7e1fd782a5293c41edd0ae1dbd75c4fdf6404d8cfe5cf2191ad1822e32877ded1675e48895e8b9898778855d3dd56636
ssdeep 192:76f0CW5P2Io4evFrDv2ZRJzCn7URRsjVJaZF:76fPWl24evFrT2ZR5Cn7UR0VJo
Entropy 5.108650
AhnLab Trojan/Win.Agent
Avira TR/Crypt.XPACK.Gen
Bitdefender Gen:Variant.CaddyWiper.2
ClamAV Win.Malware.CaddyWiper-9941573-1
Cyren W32/Trojan.WXHP-9071
ESET Win32/KillDisk.NCX trojan
Emsisoft Gen:Variant.CaddyWiper.2 (B)
IKARUS Trojan.Win32.KillDisk
K7 Trojan ( 0058f88b1 )
Lavasoft Gen:Trojan.Heur.FU.amW@aiAsbgg
McAfee Trojan-caddywiper.b
NANOAV Virus.Win32.Gen.ccmw
Quick Heal SM.mal.generic
Sophos Troj/KillDisk-G
Symantec Trojan.Gen.MBT
TACHYON Trojan/W32.Agent.9216.ABY
Trend Micro Trojan.F383D2EE
Trend Micro HouseCall Trojan.F383D2EE
Vir.IT eXplorer Trojan.Win32.CaddyWiper.DGP
VirusBlokAda Trojan.DoS.CaddyBlade
Zillya! Trojan.KillDisk.Win32.311
YARA Rules
  • rule CISA_10376640_04 : trojan wiper CADDYWIPER



           Author = "CISA Code & Media Analysis"

           Incident = "10376640"

           Date = "2022-03-23"

           Last_Modified = "20220324_1700"

           Actor = "n/a"

           Category = "Trojan Wiper"

           Family = "CADDYWIPER"

           Description = "Detects Caddy wiper samples"

           MD5_1 = "42e52b8daf63e6e26c3aa91e7e971492"

           SHA256_1 = "a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea"


           $s0 = { 44 73 52 6F 6C 65 47 65 74 50 72 69 6D 61 72 79 44 6F 6D 61 69 6E }

           $s1 = { 50 C6 45 A1 00 C6 45 A2 48 C6 45 A3 00 C6 45 A4 59 C6 }

           $s2 = { C6 45 A6 53 C6 45 A7 00 C6 45 A8 49 C6 }

           $s3 = { C6 45 B0 44 C6 45 B1 00 C6 45 B2 52 }

           $s4 = { C6 45 B8 45 C6 45 B9 00 C6 45 BA 39 }

           $s5 = { C6 45 AC 43 C6 45 AD 3A C6 45 AE 5C C6 45 AF }

           $s6 = { 55 C6 45 B0 73 C6 45 B1 65 C6 45 B2 72 C6 45 B3 }

           $s7 = { C6 45 E0 44 C6 45 E1 3A C6 45 E2 5C C6 45 E3 }

           $s8 = { 21 54 68 69 73 20 70 72 6F 67 72 61 6D 20 63 61 6E 6E 6F }


           all of them

ssdeep Matches

No matches found.

PE Metadata
Compile Date 2022-03-14 03:19:36-04:00
Import Hash ea8609d4dad999f73ec4b6f8e7b28e55
PE Sections
MD5 Name Raw Size Entropy
6194652d04e28dad063a1b6e60d110ab header 1024 1.873192
f0d4c11521fc3891965534e6c52e128b .text 7168 5.644240
d4b14cf770a6e660ba6a6e63f7c22451 .rdata 512 0.988058
0f1286f7c8817e0974ddc3ce1edc1b59 .reloc 512 0.081539
Borland Delphi 3.0 (???)

This file is a 32 bit Windows PE that has been identified as a variant of the malware family known as Caddy Wiper. Static analysis of this application indicates its primary purpose is to destroy victim user data. First the malware attempts to enumerate all files in the directory "C:\Users". The malware will then attempt to recursively overwrite files that it can access in this directory with null bytes, effectively "zeroing" the files out.

The malware will then attempt to access drives attached to the target system, starting with the drive "D:\", and recursively "zero" out all the files it can access on those drives too. Finally, the malware attempts to use the API DeviceIoControl to directly access the physical memory of attached drives. If it is able to access these drives, the malware will zero out the first 1920 bytes of the physical drives, effectively wiping its Master Boot Record and corrupting the drive.


Figure 1. - This screenshot illustrates the main structure of the malware. As illustrated, the malware's main purpose is to recursively overwrite victim user's files and physical drives with null bytes.

Figure 2. - Structure that malware uses to build null buffer. This buffer is utilized to overwrite the victim user's target files.

Figure 3. - Malware trying to zero out \\.\PHYSICALDRIVE7

Figure 4. - Malware trying to zero out \\.\PHYSICALDRIVE4

Figure 5. - Malware trying to zero out \\.\PHYSICALDRIVE3

Figure 6. - Malware attempting to zero out first 1920 bytes of a physical drive attached to the target system.


CISA recommends that users and administrators consider using the following best practices to strengthen the security posture of their organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

  • Maintain up-to-date antivirus signatures and engines.
  • Keep operating system patches up-to-date.
  • Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
  • Restrict users' ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
  • Enforce a strong password policy and implement regular password changes.
  • Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
  • Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
  • Disable unnecessary services on agency workstations and servers.
  • Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).
  • Monitor users' web browsing habits; restrict access to sites with unfavorable content.
  • Exercise caution when using removable media (e.g., USB thumb drives, external drives, CDs, etc.).
  • Scan all software downloaded from the Internet prior to executing.
  • Maintain situational awareness of the latest threats and implement appropriate Access Control Lists (ACLs).

Additional information on malware incident prevention and handling can be found in National Institute of Standards and Technology (NIST) Special Publication 800-83, "Guide to Malware Incident Prevention & Handling for Desktops and Laptops".

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What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact CISA and provide information regarding the level of desired analysis.

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Can I submit malware to CISA? Malware samples can be submitted via three methods:

CISA encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on CISA's homepage at


April 28, 2022: Initial Version

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