Notification
This report is provided "as is" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. The DHS does not endorse any commercial product or service, referenced in this bulletin or otherwise.
This document is marked TLP:WHITE. Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol, see http://www.us-cert.gov/tlp.
Summary
Description
14 files were submitted for analysis. These files are designed to encrypt a victim's system files for a ransom payment.
For a downloadable copy of IOCs, see:
Submitted Files (17)
036071786d7db553e2415ec2e71f3967baf51bdc31d0a640aa4afb87d3ce3050 (samsam.exe)
0f2c5c39494f15b7ee637ad5b6b5d00a3e2f407b4f27d140cd5a821ff08acfac (samsam.exe)
32445c921079aa3e26a376d70ef6550bafeb1f6b0b7037ef152553bb5dad116f (selfdel.exe)
45e00fe90c8aa8578fce2b305840e368d62578c77e352974da6b8f8bc895d75b (samsam.exe)
553967d05b83364c6954d2b55b8cfc2ea3808a17c268b2eee49090e71976ba29 (553967d05b83364c6954d2b55b8cfc...)
58ef87523184d5df3ed1568397cea65b3f44df06c73eadeb5d90faebe4390e3e (samsam.exe)
6245a51e78526c25510d0aa0909576119fdf0244619f670036538063b88f1c21 (HELP_DECRYPT_YOUR_FILES.html)
6bc2aa391b8ef260e79b99409e44011874630c2631e4487e82b76e5cb0a49307 (samsam.exe)
7aa585e6fd0a895c295c4bea2ddb071eed1e5775f437602b577a54eef7f61044 (samsam.exe)
89b4abb78970cd524dd887053d5bcd982534558efdf25c83f96e13b56b4ee805 (samsam.exe)
939efdc272e8636fd63c1b58c2eec94cf10299cd2de30c329bd5378b6bbbd1c8 (samsam.exe)
946dd4c4f3c78e7e4819a712c7fd6497722a3d616d33e3306a556a9dc99656f4 (samsam.exe)
979692a34201f9fc1e1c44654dc8074a82000946deedfdf6b8985827da992868 (samsam.exe)
97d27e1225b472a63c88ac9cfb813019b72598b9dd2d70fe93f324f7d034fb95 (del.exe)
a763ed678a52f77a7b75d55010124a8fccf1628eb4f7a815c6d635034227177e (samsam.exe)
e682ac6b874e0a6cfc5ff88798315b2cb822d165a7e6f72a5eb74e6da451e155 (samsam.exe)
ffef0f1c2df157e9c2ee65a12d5b7b0f1301c4da22e7e7f3eac6b03c6487a626 (samsam.exe)
Domains (10)
anonyme.com
evilsecure9.wordpress.com
followsec7.wordpress.com
key88secu7.wordpress.com
keytwocode.wordpress.com
lordsecure4u.wordpress.com
payforsecure7.wordpress.com
secangel7d.wordpress.com
union83939k.wordpress.com
zeushelpu.wordpress.com
Findings
0f2c5c39494f15b7ee637ad5b6b5d00a3e2f407b4f27d140cd5a821ff08acfac
Tags
dropperransomwaretrojan
Details
Name |
samsam.exe |
Size |
218624 bytes |
Type |
PE32 executable (GUI) Intel 80386 Mono/.Net assembly, for MS Windows |
MD5 |
a14ea969014b1145382ffcd508d10156 |
SHA1 |
ff6aa732320d21697024994944cf66f7c553c9cd |
SHA256 |
0f2c5c39494f15b7ee637ad5b6b5d00a3e2f407b4f27d140cd5a821ff08acfac |
SHA512 |
73f28bed4ee700e15d1c0eb9871e37bdda77e3ef3c14b63a1597b9628e7407dc31f8382e0ec52c8c65f68c00a4f321f5971359f865eb35b35dc62e9f5e8e7be1 |
ssdeep |
3072:ZVdp01i6vcHV1LI5FLV0pZeZKfOJizjrBnNtRg+ur199J+n9fCbP:Za1i6UHVyLV0poZa1jrD099on9 |
Entropy |
6.249245 |
Antivirus
Ahnlab |
Trojan/Win32.Samas |
Antiy |
Trojan/Win32.SGeneric |
Avira |
TR/Ransom.lhumd |
BitDefender |
Generic.Ransom.SamSam.12451789 |
ClamAV |
Win.Trojan.Samas-1 |
Cyren |
W32/Trojan.MPPP-7951 |
ESET |
MSIL/Filecoder.AR trojan |
Emsisoft |
Generic.Ransom.SamSam.12451789 (B) |
Ikarus |
Trojan-Ransom.SamSam |
K7 |
Trojan ( 700000121 ) |
McAfee |
Ransomware-SAMAS!A14EA969014B |
Microsoft Security Essentials |
Ransom:MSIL/Samas.A |
NANOAV |
Trojan.Win32.Ransom.eamswz |
Quick Heal |
Trojan.Inject.TL3 |
Sophos |
Troj/RansmSam-A |
Symantec |
Trojan.Gen.2 |
Systweak |
malware.gen-r |
TrendMicro |
Ransom_CRYPSAM.B |
TrendMicro House Call |
Ransom_CRYPSAM.B |
Vir.IT eXplorer |
Trojan.Win32.MSIL9.BGXA |
VirusBlokAda |
Trojan-Ransom.MSIL.Samas |
Zillya! |
Dropper.Agent.Win32.229787 |
Yara Rules
No matches found.
ssdeep Matches
97 |
036071786d7db553e2415ec2e71f3967baf51bdc31d0a640aa4afb87d3ce3050 |
PE Metadata
Compile Date |
2016-01-05 19:14:43-05:00 |
Import Hash |
f34d5f2d4577ed6d9ceec516c1f5a744 |
Company Name |
Microsoft |
File Description |
MicrosoftSAM |
Internal Name |
samsam.exe |
Legal Copyright |
Copyright \xa9 2014 |
Original Filename |
samsam.exe |
Product Name |
MicrosoftSAM |
Product Version |
2.4.8.4 |
PE Sections
MD5 |
Name |
Raw Size |
Entropy |
37c3e95eb9901183e02df0ba1de6caf2 |
header |
512 |
2.774592 |
7a556f246357051b2d82ea445571ddbb |
.text |
216064 |
6.270810 |
d0b581056989efaa1de31a61a8f4a9ec |
.rsrc |
1536 |
4.110334 |
06441ad348b483e2458a535949e809cf |
.reloc |
512 |
0.101910 |
Packers/Compilers/Cryptors
Microsoft Visual C# v7.0 / Basic .NET |
Relationships
0f2c5c3949... |
Connected_To |
union83939k.wordpress.com |
0f2c5c3949... |
Dropped |
6245a51e78526c25510d0aa0909576119fdf0244619f670036538063b88f1c21 |
0f2c5c3949... |
Dropped |
32445c921079aa3e26a376d70ef6550bafeb1f6b0b7037ef152553bb5dad116f |
0f2c5c3949... |
Dropped |
97d27e1225b472a63c88ac9cfb813019b72598b9dd2d70fe93f324f7d034fb95 |
Description
This file is a 32-bit Windows .NET compiled executable designed to encrypt victim system files for a ransom payment. This file is a variant of SamSam ransomware. It contains two embedded 32-bit Windows executables in its resource section:
--Begin resource-- "samsam.del.exe" ==> del.exe (SDelete) designed to securely delete files "samsam.selfdel.exe" ==> selfdel.exe designed to delete the SamSam ransomware from the victim’s system --End resource--
It installs the embedded files into the following directory:
--Begin files installed-- %Currentdirectory%\del.exe %Currentdirectory%\Selfdel.exe --End files installed--
This file is designed to accept an input text file as the command line argument. The input text file contains an RSA public key in the following format:
--Begin RSA public key-- "<RSAKeyValue><Modulus>Base64 encoded RSA public key</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>" --End RSA public key--
The input text file was not available for analysis.
Displayed below is the code snippet designed to accept an input text file as the command-line argument:
--Begin command line argument-- private static void Main(string[] args) { if (args.Length != 1) { return; } if (!string.IsNullOrEmpty(args[0])) { Program.publickey = File.ReadAllText(args[0]); } Program.create_from_resource(); --End command line argument--
It searches the drives installed on the victim system for files with the following file extensions:
--Begin file extensions-- "xls",".xlsx",".pdf",".doc",".docx",".ppt",".pptx",".txt",".dwg",".bak",".bkf",".pst",".dbx",".zip",".rar",".mdb",".asp",".aspx",".html",".htm",".dbf",".3dm",".3ds",".3fr",".jar",".3g2",".xml",".png",".tif",".3gp",".java",".jpe",".jpeg",".jpg",".jsp",".php",".3pr",".7z",".ab4",".accdb",".accde",".accdr",".accdt",".ach",".kbx",".acr",".act",".adb",".ads",".agdl",".ai",".ait",".al",".apj",".arw",".asf",".asm",".asx",".avi",".awg",".back",".backup",".backupdb",".pbl",".bank",".bay",".bdb",".bgt",".bik",".bkp",".blend",".bpw",".c",".cdf",".cdr",".cdr3",".cdr4",".cdr5",".cdr6",".cdrw",".cdx",".ce1",".ce2",".cer",".cfp",".cgm",".cib",".class",".cls",".cmt",".cpi",".cpp",".cr2",".craw",".crt",".crw",".phtml",".php5",".cs",".csh",".csl",".tib",".csv",".dac",".db",".db3",".db-journal",".dc2",".dcr",".dcs",".ddd",".ddoc",".ddrw",".dds",".der",".des",".design",".dgc",".djvu",".dng",".dot",".docm",".dotm",".dotx",".drf",".drw",".dtd",".dxb",".dxf",".dxg",".eml",".eps",".erbsql",".erf",".exf",".fdb",".ffd",".fff",".fh",".fmb",".fhd",".fla",".flac",".flv",".fpx",".fxg",".gray",".grey",".gry",".h",".hbk",".hpp",".ibank",".ibd",".ibz",".idx",".iif",".iiq",".incpas",".indd",".kc2",".kdbx",".kdc",".key",".kpdx",".lua",".m",".m4v",".max",".mdc",".mdf",".mef",".mfw",".mmw",".moneywell",".mos",".mov",".mp3",".mp4",".mpg",".mrw",".msg",".myd",".nd",".ndd",".nef",".nk2",".nop",".nrw",".ns2",".ns3",".ns4",".nsd",".nsf",".nsg",".nsh",".nwb",".nx2",".nxl",".nyf",".oab",".obj",".odb",".odc",".odf",".odg",".odm",".odp",".ods",".odt",".oil",".orf",".ost",".otg",".oth",".otp",".ots",".ott",".p12",".p7b",".p7c",".pab",".pages",".pas",".pat",".pcd",".pct",".pdb",".pdd",".pef",".pem",".pfx",".pl",".plc",".pot",".potm",".potx",".ppam",".pps",".ppsm",".ppsx",".pptm",".prf",".ps",".psafe3",".psd",".pspimage",".ptx",".py",".qba",".qbb",".qbm",".qbr",".qbw",".qbx",".qby",".r3d",".raf",".rat",".raw",".rdb",".rm",".rtf",".rw2",".rwl",".rwz",".s3db",".sas7bdat",".say",".sd0",".sda",".sdf",".sldm",".sldx",".sql",".sqlite",".sqlite3",".sqlitedb",".sr2",".srf",".srt",".srw",".st4",".st5",".st6",".st7",".st8",".std",".sti",".stw",".stx",".svg",".swf",".sxc",".sxd",".sxg",".sxi",".sxi",".sxm",".sxw",".tex",".tga",".thm",".tlg",".vob",".war",".wallet",".wav",".wb2",".wmv",".wpd",".wps",".x11",".x3f",".xis",".xla",".xlam",".xlk",".xlm",".xlr",".xlsb",".xlsm",".xlt",".xltm",".xltx",".xlw",".ycbcra",".yuv" --End file extensions--
The malware avoids encrypting files in the "Windows", "Reference Assemblies\\Microsoft", and "Recycle.bin" folders:
Displayed below is the code snippet used to avoid encrypting files in the folders:
--Begin code-- if (path != Program.sysdir + "Windows" && !path.Contains("Reference Assemblies\\Microsoft") && !path.Contains("Recycle.Bin")) --End code--
It randomly generates the following keys for encrypting the target files:
--Begin randomly generates keys-- AES key (16 bytes) AES IV (16 bytes) Signature key (64 bytes) for SHA256 HMAC key calculation --End randomly generates keys--
Displayed below is the code snippet for generating the unique keys for a target file:
--Begin key generation-- public static string Encrypt(string plainFilePath, string encryptedFilePath, string manifestFilePath, string rsaKey) { byte[] signatureKey = encc.GenerateRandom(64); ===> HMAC key byte[] key = encc.GenerateRandom(16); ==> Rijndael key byte[] iv = encc.GenerateRandom(16); ==> Rijndael IV encc.EncryptFile(plainFilePath, encryptedFilePath, key, iv, signatureKey, rsaKey); return null; --End key generation--
It reads the target file into memory and encrypts it using an AES algorithm in CBC mode with the generated AES keys. The encrypted data from the original file is stored into a newly created file. This file has the same name as the original file, but has an ".encryptedRSA" extension. The ransomware calculates a SHA-256 HMAC of the encrypted data of the file.
The generated keys are encrypted using the RSA public key from the key file. The malware Base64 encodes and prepends the following data in XML format at the beginning of the encrypted file:
--Begin Base64 encodes data-- AES key, encrypted with RSA public key AES IV, encrypted with RSA public key SHA-256H MAC of the encrypted file data HMAC key, encrypted with RSA public key --End Base64 encodes data--
Displayed below is the code used to RSA encrypt and Base64 encode the data prepended at the beginning of each encrypted file.
--Begin encrypting and encoding-- byte[] inArray = encc.CalculateSignature(encryptedFilePath, signatureKey); string text = Convert.ToBase64String(encc.RSAEncryptBytes(key, rsaKey)); string text2 = Convert.ToBase64String(encc.RSAEncryptBytes(iv, rsaKey)); string text3 = Convert.ToBase64String(inArray); string text4 = Convert.ToBase64String(encc.RSAEncryptBytes(signatureKey, rsaKey)); string str = string.Concat(new object[] { "<MtAeSKeYForFile>", encc.sn, "<Key>", text, ==> Base64 encoded AES key, encrypted with RSA public key with OAEP padding "</Key>", encc.sn, "<IV>", text2, ==> Base64 encoded AES IV, encrypted with RSA public key with OAEP padding "</IV>", encc.sn, "<Value>", text3, ==> Base64 encoded SHA-256 HMAC of the encrypted file data "</Value>", encc.sn, "<EncryptedKey>", text4, ==> Base64 encoded HMAC key, encrypted with RSA public key with OAEP padding "</EncryptedKey>", encc.sn, "<OriginalFileLength>", fileInfo.Length, ==> The length of the original file "</OriginalFileLength>", encc.sn, "</MtAeSKeYForFile>" }); --End encrypting and encoding--
Following the encryption of the victim’s files, the ransomware executes "selfdel.exe" to delete itself from the system and installs the ransomware note "HELP_DECRYPT_YOUR_FILES.html” onto the victim’s system.
Displayed below is the embedded blog and Bitcoin address for the ransomware note:
--Begin blog and Bitcoin address-- Blog address: "http[:]//union83939k.wordpress.com" Bitcoin address: 19CbDoaZDLTzkkT1uQrMPM42AUvfQN4Kds --End blog and Bitcoin address--
7aa585e6fd0a895c295c4bea2ddb071eed1e5775f437602b577a54eef7f61044
Tags
ransomwaretrojan
Details
Name |
samsam.exe |
Size |
218112 bytes |
Type |
PE32 executable (GUI) Intel 80386 Mono/.Net assembly, for MS Windows |
MD5 |
14721036e16587594ad950d4f2db5f27 |
SHA1 |
ed1797c282f0817d2ad8f878f8dd50ab062501ac |
SHA256 |
7aa585e6fd0a895c295c4bea2ddb071eed1e5775f437602b577a54eef7f61044 |
SHA512 |
4d9e75850713f0bf6892fca8d74f462a5b2c0ccec2ed089fd830b8babcce7aedbd3bcb56e25c81cb6bf285bba9111ef89913d0c665593b2ba8da5f57d9505d32 |
ssdeep |
3072:gUOsdp01i6vcHV1LI5FLV0pZeZKfOJizjrBnNtRg+ur199JWbk9f7b1v:gzL1i6UHVyLV0poZa1jrD099Qbk9V |
Entropy |
6.248108 |
Antivirus
Ahnlab |
Trojan/Win32.Samas |
Antiy |
Trojan[Ransom]/MSIL.Samas |
Avira |
TR/Ransom.lhumd |
BitDefender |
Generic.Ransom.SamSam.B120689A |
Cyren |
W32/Trojan.HBQK-8340 |
ESET |
a variant of MSIL/Filecoder.AR trojan |
Emsisoft |
Generic.Ransom.SamSam.B120689A (B) |
Ikarus |
Trojan-Ransom.SamSam |
K7 |
Trojan ( 700000121 ) |
McAfee |
Ransomware-SAMAS!14721036E165 |
Microsoft Security Essentials |
Ransom:MSIL/Samas.A |
NANOAV |
Trojan.Win32.Samas.eajeha |
Quick Heal |
Trojan.Inject.TL3 |
Sophos |
Troj/RansmSam-A |
Symantec |
Ransom.SamSam!gen1 |
Systweak |
trojan-spy.filecryptor |
TrendMicro |
Ransom_.2933F726 |
TrendMicro House Call |
Ransom_.2933F726 |
Vir.IT eXplorer |
Trojan.Win32.Atros3.CWX |
VirusBlokAda |
Trojan-Ransom.MSIL.Samas |
Zillya! |
Trojan.Filecoder.Win32.2108 |
Yara Rules
No matches found.
ssdeep Matches
No matches found.
Packers/Compilers/Cryptors
Microsoft Visual C# v7.0 / Basic .NET |
Relationships
7aa585e6fd... |
Dropped |
6245a51e78526c25510d0aa0909576119fdf0244619f670036538063b88f1c21 |
7aa585e6fd... |
Dropped |
32445c921079aa3e26a376d70ef6550bafeb1f6b0b7037ef152553bb5dad116f |
7aa585e6fd... |
Dropped |
97d27e1225b472a63c88ac9cfb813019b72598b9dd2d70fe93f324f7d034fb95 |
7aa585e6fd... |
Connected_To |
union83939k.wordpress.com |
Description
This file is a 32-bit Windows .NET compiled executable designed to encrypt victim system files for a ransom payment. This file is a variant of SamSam ransomware. It contains two embedded 32-bit Windows executables in its resource section:
--Begin resource-- "samsam.del.exe" ==> del.exe (SDelete) designed to securely delete files "samsam.selfdel.exe" ==> selfdel.exe designed to delete the SamSam ransomware from the victim’s system --End resource--
It installs the embedded files into the following directory:
--Begin files installed-- %Currentdirectory%\del.exe %Currentdirectory%\Selfdel.exe --End files installed--
This file is designed to accept an input text file as the command line argument. The input text file contains an RSA public key in the following format:
--Begin RSA public key-- "<RSAKeyValue><Modulus>Base64 encoded RSA public key</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>" --End RSA public key--
The input text file was not available for analysis.
Displayed below is the code snippet designed to accept an input text file as the command-line argument:
--Begin command line argument-- private static void Main(string[] args) { if (args.Length != 1) { return; } if (!string.IsNullOrEmpty(args[0])) { Program.publickey = File.ReadAllText(args[0]); } Program.create_from_resource(); --End command line argument--
It searches the drives installed on the victim system for files with the following file extensions:
--Begin file extensions-- "xls",".xlsx",".pdf",".doc",".docx",".ppt",".pptx",".txt",".dwg",".bak",".bkf",".pst",".dbx",".zip",".rar",".mdb",".asp",".aspx",".html",".htm",".dbf",".3dm",".3ds",".3fr",".jar",".3g2",".xml",".png",".tif",".3gp",".java",".jpe",".jpeg",".jpg",".jsp",".php",".3pr",".7z",".ab4",".accdb",".accde",".accdr",".accdt",".ach",".kbx",".acr",".act",".adb",".ads",".agdl",".ai",".ait",".al",".apj",".arw",".asf",".asm",".asx",".avi",".awg",".back",".backup",".backupdb",".pbl",".bank",".bay",".bdb",".bgt",".bik",".bkp",".blend",".bpw",".c",".cdf",".cdr",".cdr3",".cdr4",".cdr5",".cdr6",".cdrw",".cdx",".ce1",".ce2",".cer",".cfp",".cgm",".cib",".class",".cls",".cmt",".cpi",".cpp",".cr2",".craw",".crt",".crw",".phtml",".php5",".cs",".csh",".csl",".tib",".csv",".dac",".db",".db3",".db-journal",".dc2",".dcr",".dcs",".ddd",".ddoc",".ddrw",".dds",".der",".des",".design",".dgc",".djvu",".dng",".dot",".docm",".dotm",".dotx",".drf",".drw",".dtd",".dxb",".dxf",".dxg",".eml",".eps",".erbsql",".erf",".exf",".fdb",".ffd",".fff",".fh",".fmb",".fhd",".fla",".flac",".flv",".fpx",".fxg",".gray",".grey",".gry",".h",".hbk",".hpp",".ibank",".ibd",".ibz",".idx",".iif",".iiq",".incpas",".indd",".kc2",".kdbx",".kdc",".key",".kpdx",".lua",".m",".m4v",".max",".mdc",".mdf",".mef",".mfw",".mmw",".moneywell",".mos",".mov",".mp3",".mp4",".mpg",".mrw",".msg",".myd",".nd",".ndd",".nef",".nk2",".nop",".nrw",".ns2",".ns3",".ns4",".nsd",".nsf",".nsg",".nsh",".nwb",".nx2",".nxl",".nyf",".oab",".obj",".odb",".odc",".odf",".odg",".odm",".odp",".ods",".odt",".oil",".orf",".ost",".otg",".oth",".otp",".ots",".ott",".p12",".p7b",".p7c",".pab",".pages",".pas",".pat",".pcd",".pct",".pdb",".pdd",".pef",".pem",".pfx",".pl",".plc",".pot",".potm",".potx",".ppam",".pps",".ppsm",".ppsx",".pptm",".prf",".ps",".psafe3",".psd",".pspimage",".ptx",".py",".qba",".qbb",".qbm",".qbr",".qbw",".qbx",".qby",".r3d",".raf",".rat",".raw",".rdb",".rm",".rtf",".rw2",".rwl",".rwz",".s3db",".sas7bdat",".say",".sd0",".sda",".sdf",".sldm",".sldx",".sql",".sqlite",".sqlite3",".sqlitedb",".sr2",".srf",".srt",".srw",".st4",".st5",".st6",".st7",".st8",".std",".sti",".stw",".stx",".svg",".swf",".sxc",".sxd",".sxg",".sxi",".sxi",".sxm",".sxw",".tex",".tga",".thm",".tlg",".vob",".war",".wallet",".wav",".wb2",".wmv",".wpd",".wps",".x11",".x3f",".xis",".xla",".xlam",".xlk",".xlm",".xlr",".xlsb",".xlsm",".xlt",".xltm",".xltx",".xlw",".ycbcra",".yuv" --End file extensions--
The malware avoids encrypting files in the "Windows", "Reference Assemblies\\Microsoft", and "Recycle.bin" folders:
Displayed below is the code snippet used to avoid encrypting files in the folders:
--Begin code-- if (path != Program.sysdir + "Windows" && !path.Contains("Reference Assemblies\\Microsoft") && !path.Contains("Recycle.Bin")) --End code--
It randomly generates the following keys for encrypting the target files:
--Begin randomly generates keys-- AES key (16 bytes) AES IV (16 bytes) Signature key (64 bytes) for SHA256 HMAC key calculation --End randomly generates keys--
Displayed below is the code snippet for generating the unique keys for a target file:
--Begin key generation-- public static string Encrypt(string plainFilePath, string encryptedFilePath, string manifestFilePath, string rsaKey) { byte[] signatureKey = encc.GenerateRandom(64); ===> HMAC key byte[] key = encc.GenerateRandom(16); ==> Rijndael key byte[] iv = encc.GenerateRandom(16); ==> Rijndael IV encc.EncryptFile(plainFilePath, encryptedFilePath, key, iv, signatureKey, rsaKey); return null; --End key generation--
It reads the target file into memory and encrypts it using an AES algorithm in CBC mode with the generated AES keys. The encrypted data from the original file is stored into a newly created file. This file has the same name as the original file, but has an ".encryptedRSA" extension. The ransomware calculates a SHA-256 HMAC of the encrypted data of the file.
The generated keys are encrypted using the RSA public key from the key file. The malware Base64 encodes and prepends the following data in XML format at the beginning of the encrypted file:
--Begin Base64 encodes data-- AES key, encrypted with RSA public key AES IV, encrypted with RSA public key SHA-256H MAC of the encrypted file data HMAC key, encrypted with RSA public key --End Base64 encodes data--
Displayed below is the code used to RSA encrypt and Base64 encode the data prepended at the beginning of each encrypted file.
--Begin encrypting and encoding-- byte[] inArray = encc.CalculateSignature(encryptedFilePath, signatureKey); string text = Convert.ToBase64String(encc.RSAEncryptBytes(key, rsaKey)); string text2 = Convert.ToBase64String(encc.RSAEncryptBytes(iv, rsaKey)); string text3 = Convert.ToBase64String(inArray); string text4 = Convert.ToBase64String(encc.RSAEncryptBytes(signatureKey, rsaKey)); string str = string.Concat(new object[] { "<MtAeSKeYForFile>", encc.sn, "<Key>", text, ==> Base64 encoded AES key, encrypted with RSA public key with OAEP padding "</Key>", encc.sn, "<IV>", text2, ==> Base64 encoded AES IV, encrypted with RSA public key with OAEP padding "</IV>", encc.sn, "<Value>", text3, ==> Base64 encoded SHA-256 HMAC of the encrypted file data "</Value>", encc.sn, "<EncryptedKey>", text4, ==> Base64 encoded HMAC key, encrypted with RSA public key with OAEP padding "</EncryptedKey>", encc.sn, "<OriginalFileLength>", fileInfo.Length, ==> The length of the original file "</OriginalFileLength>", encc.sn, "</MtAeSKeYForFile>" }); --End encrypting and encoding--
Following the encryption of the victim’s files, the ransomware executes "selfdel.exe" to delete itself from the system and installs the ransomware note "HELP_DECRYPT_YOUR_FILES.html” onto the victim’s system.
Displayed below is the embedded blog and Bitcoin address for the ransomware note:
--Begin blog and Bitcoin address-- blog address: "http://union83939k.wordpress.com" Bitcoin address: 19CbDoaZDLTzkkT1uQrMPM42AUvfQN4Kds --End blog and Bitcoin address--
union83939k.wordpress.com
URLs
- http://union83939k.wordpress.com
Whois
Domain Name: WORDPRESS.COM Registry Domain ID: 21242797_DOMAIN_COM-VRSN Registrar WHOIS Server: whois.markmonitor.com Registrar URL: http://www.markmonitor.com Updated Date: 2017-01-12T22:53:10Z Creation Date: 2000-03-03T12:13:23Z Registry Expiry Date: 2020-03-03T12:13:23Z Registrar: MarkMonitor Inc. Registrar IANA ID: 292 Registrar Abuse Contact Email: abusecomplaints@markmonitor.com Registrar Abuse Contact Phone: +1.2083895740 Domain Status: clientDeleteProhibited https://icann.org/epp#clientDeleteProhibited Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited Domain Status: clientUpdateProhibited https://icann.org/epp#clientUpdateProhibited Domain Status: serverDeleteProhibited https://icann.org/epp#serverDeleteProhibited Domain Status: serverTransferProhibited https://icann.org/epp#serverTransferProhibited Domain Status: serverUpdateProhibited https://icann.org/epp#serverUpdateProhibited Name Server: NS1.WORDPRESS.COM Name Server: NS2.WORDPRESS.COM Name Server: NS3.WORDPRESS.COM Name Server: NS4.WORDPRESS.COM DNSSEC: unsigned URL of the ICANN Whois Inaccuracy Complaint Form: https://www.icann.org/wicf/ >>> Last update of whois database: 2018-03-27T18:16:17Z <<< NetRange: 192.0.64.0 - 192.0.127.255 CIDR: 192.0.64.0/18 NetName: AUTOMATTIC NetHandle: NET-192-0-64-0-1 Parent: NET192 (NET-192-0-0-0-0) NetType: Direct Assignment OriginAS: AS2635 Organization: Automattic, Inc (AUTOM-93) RegDate: 2012-11-20 Updated: 2012-11-20 Ref: https://whois.arin.net/rest/net/NET-192-0-64-0-1
OrgName: Automattic, Inc OrgId: AUTOM-93 Address: 60 29th Street #343 City: San Francisco StateProv: CA PostalCode: 94110 Country: US RegDate: 2011-10-05 Updated: 2013-11-01 Ref: https://whois.arin.net/rest/org/AUTOM-93
OrgAbuseHandle: ABUSE3970-ARIN OrgAbuseName: Abuse OrgAbusePhone: +1-877-273-8550 OrgAbuseEmail: abuse@automattic.com OrgAbuseRef: https://whois.arin.net/rest/poc/ABUSE3970-ARIN
OrgTechHandle: NOC12276-ARIN OrgTechName: NOC OrgTechPhone: +1-877-273-8550 OrgTechEmail: ipadmin@automattic.com OrgTechRef: https://whois.arin.net/rest/poc/NOC12276-ARIN
OrgNOCHandle: NOC12276-ARIN OrgNOCName: NOC OrgNOCPhone: +1-877-273-8550 OrgNOCEmail: ipadmin@automattic.com OrgNOCRef: https://whois.arin.net/rest/poc/NOC12276-ARIN
Relationships
union83939k.wordpress.com |
Connected_From |
0f2c5c39494f15b7ee637ad5b6b5d00a3e2f407b4f27d140cd5a821ff08acfac |
union83939k.wordpress.com |
Connected_From |
7aa585e6fd0a895c295c4bea2ddb071eed1e5775f437602b577a54eef7f61044 |
036071786d7db553e2415ec2e71f3967baf51bdc31d0a640aa4afb87d3ce3050
Tags
dropperransomwaretrojan
Details
Name |
samsam.exe |
Size |
218624 bytes |
Type |
PE32 executable (GUI) Intel 80386 Mono/.Net assembly, for MS Windows |
MD5 |
fe998080463665412b65850828bce41f |
SHA1 |
203bb8ec1da6b237a092bab71fa090849c7db9bd |
SHA256 |
036071786d7db553e2415ec2e71f3967baf51bdc31d0a640aa4afb87d3ce3050 |
SHA512 |
9ade6edde3f063fc935f53366ffc9cb6cf7e17691d22fd2fe107d779da3b61eaed006ef7679b456bc16aca8b686d035f09aaf42bf06fa62b872e0a89046994eb |
ssdeep |
3072:bVdp01i6vcHV1LI5FLV0pZeZKfOJizjrBnNtRg+ur199J+n9fCbM:ba1i6UHVyLV0poZa1jrD099on9 |
Entropy |
6.249304 |
Antivirus
Ahnlab |
Trojan/Win32.Samas |
Antiy |
Trojan/Win32.SGeneric |
Avira |
TR/Ransom.lhumd |
BitDefender |
Generic.Ransom.SamSam.CDB17A36 |
ClamAV |
Win.Trojan.Samas-1 |
Cyren |
W32/SamSam.D.gen!Eldorado |
ESET |
MSIL/Filecoder.AR trojan |
Emsisoft |
Generic.Ransom.SamSam.CDB17A36 (B) |
Ikarus |
Trojan-Ransom.SamSam |
K7 |
Trojan ( 700000121 ) |
McAfee |
Ransomware-SAMAS!FE9980804636 |
Microsoft Security Essentials |
Ransom:MSIL/Samas.A |
NANOAV |
Trojan.Win32.Ransom.eamenb |
NetGate |
Trojan.Win32.Malware |
Quick Heal |
Trojan.Inject.TL3 |
Sophos |
Troj/RansmSam-A |
Symantec |
Ransom.SamSam!gen1 |
Systweak |
malware.gen-r |
TrendMicro |
Ransom_.2933F726 |
TrendMicro House Call |
Ransom_.2933F726 |
Vir.IT eXplorer |
Trojan.Win32.MSIL9.BGXA |
VirusBlokAda |
Trojan-Ransom.MSIL.Samas |
Zillya! |
Dropper.Agent.Win32.229787 |
Yara Rules
No matches found.
ssdeep Matches
97 |
0f2c5c39494f15b7ee637ad5b6b5d00a3e2f407b4f27d140cd5a821ff08acfac |
Packers/Compilers/Cryptors
Microsoft Visual C# v7.0 / Basic .NET |
Relationships
036071786d... |
Dropped |
6245a51e78526c25510d0aa0909576119fdf0244619f670036538063b88f1c21 |
036071786d... |
Dropped |
32445c921079aa3e26a376d70ef6550bafeb1f6b0b7037ef152553bb5dad116f |
036071786d... |
Dropped |
97d27e1225b472a63c88ac9cfb813019b72598b9dd2d70fe93f324f7d034fb95 |
036071786d... |
Connected_To |
keytwocode.wordpress.com |
Description
This file is a 32-bit Windows .NET compiled executable designed to encrypt victim system files for a ransom payment. This file is a variant of SamSam ransomware. It contains two embedded 32-bit Windows executables in its resource section:
--Begin resource-- "samsam.del.exe" ==> del.exe (SDelete) designed to securely delete files "samsam.selfdel.exe" ==> selfdel.exe designed to delete the SamSam ransomware from the victim’s system --End resource--
It installs the embedded files into the following directory:
--Begin files installed-- %Currentdirectory%\del.exe %Currentdirectory%\Selfdel.exe --End files installed--
This file is designed to accept an input text file as the command line argument. The input text file contains an RSA public key in the following format:
--Begin RSA public
|