OSX/Flashback.O sample + some domains
Archived: 2026-04-06 00:03:35 UTC
OSX/Flashback.O sample + some domains
1. A few hours after I posted the Flashback.K, someone anonymously uploaded Flashback.O sample (thank
you very much!), which I am posting below. Like in the first case, it is a payload binary from a victim, not the downloader,
which makes it impossible to install.  If you succeed or have a binary that installs, please share. I personally have not tried
to run them yet, did not have a vm.
2. Matt Thompson from Unveillance emailed his comments about the Flackback.K sample please see the quote below.
3. Update April 11 - I will put domains and URLs in a separate post because they relate to various versions of Flashback,
not v.40/O
Download
From  Matt Thompson regarding the previous Flashback.K
This is the exact payload binary I have been working with.
I extracted the x86_64 architecture into a thin binary.
At 0x10000158e it sets up an RC4 identity Sbox.
At 0x1000015b2 it starts the RC4 KSA mix with the Hardware UUID. r9
contains the pointer to the UUID string
0x1000041f0 contains the ciphertext length.
0x100004200 is the beginning of 4275 bytes of ciphertext.
0x1000041e8 contains a flag indicating if the data block is encrypted or
not. If this is set to 1 the code just memcpy()'s the data into a
malloc'd buffer rather than decrypting with RC4.
If the Hardware UUID were available from the machine that downloaded
this binary, it would be trivial to write the plaintext back into the
binary and set 0x1000041e8 to 1.
Automated Scans
Virustotal
SHA256:     228be46149dd6efe9c57c881cc057d5dc1cfb759f9e9be8445f1d9d2d68875b3
SHA1:     62121738530d17292a75d17421bcd76a4051cad8
MD5:     782c4d24d406538498c1fb79fa0f6d62
File size:     394.2 KB ( 403676 bytes )
http://contagiodump.blogspot.com/2012/04/osxflashbacko-sample-some-domains.html
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File name:     FlashBack.O_ 782C4D24D406538498C1FB79FA0F6D62
File type:     unknown
Detection ratio:     19 / 42
Analysis date:     2012-04-11 01:15:36 UTC ( 38 minutes ago )
Antiy-AVL     Trojan/OSX.Flashfake     20120410
BitDefender     MAC.OSX.Trojan.FlashBack.O     20120411
ClamAV     OSX.Flashback-12     20120411
Comodo     UnclassifiedMalware     20120410
DrWeb     BackDoor.Flashback.40     20120411
Emsisoft     Trojan-Downloader.OSX.Flashfake!IK     20120410
F-Secure     MAC.OSX.Trojan.FlashBack.O     20120410
Fortinet     OSX/Flshplyr.A     20120411
GData     MAC.OSX.Trojan.FlashBack.O     20120411
Ikarus     Trojan-Downloader.OSX.Flashfake     20120411
Jiangmin     TrojanDownloader.OSX.w     20120410
Kaspersky     Trojan-Downloader.OSX.Flashfake.ae     20120410
Microsoft     Backdoor:MacOS_X/Flashback.E     20120411
NOD32     OSX/Flashback.I     20120410
nProtect     MAC.OSX.Trojan.FlashBack.O     20120410
Sophos     OSX/Flshplyr-A     20120411
Symantec     OSX.Flashback.K     20120411
TheHacker     -     20120410
TrendMicro     OSX_FLASHBACK.A     20120411
TrendMicro-HouseCall     OSX_FLASHBACK.A     20120411
6144:7tC8qm/SOIMr5lGsl1SFBu5w7FyR5ifPhebUUCNQQFJHvC4SODuanMiiK:Rvqw5lGsl1SFBuVRAZGUUCeQnvR52K
TrID
Java Bytecode (53.2%)
Mac OS X Universal Binary executable (35.5%)
HSC music composer song (11.2%)
ExifTool
MIMEType.................: application/octet-stream
FileType.................: Mach-O fat binary executable
CPUCount.................: 2
ObjectFileType...........: Dynamically bound shared library
CPUType..................: x86 64-bit, x86
CPUSubtype...............: i386 (all) 64-bit, i386 (all)
First seen by VirusTotal
2012-04-05 17:06:28 UTC ( 5 days, 8 hours ago )
Last seen by VirusTotal
2012-04-11 01:15:36 UTC ( 38 minutes ago )
File names (max. 25)
   1. FlashBack.O_ 782C4D24D406538498C1FB79FA0F6D62
http://contagiodump.blogspot.com/2012/04/osxflashbacko-sample-some-domains.html
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Source: http://contagiodump.blogspot.com/2012/04/osxflashbacko-sample-some-domains.html
http://contagiodump.blogspot.com/2012/04/osxflashbacko-sample-some-domains.html
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