<s>
TeslaCrypt	B-Application
was	O
a	O
ransomware	O
trojan	O
.	O
</s>
<s>
In	O
its	O
early	O
forms	O
,	O
TeslaCrypt	B-Application
targeted	O
game-play	O
data	O
for	O
specific	O
computer	O
games	O
.	O
</s>
<s>
In	O
its	O
original	O
,	O
game-player	O
campaign	O
,	O
upon	O
infection	O
the	O
malware	O
searched	O
for	O
185	O
file	O
extensions	O
related	O
to	O
40	O
different	O
games	O
,	O
which	O
include	O
the	O
Call	B-Application
of	I-Application
Duty	I-Application
series	O
,	O
World	B-Protocol
of	I-Protocol
Warcraft	I-Protocol
,	O
Minecraft	B-Application
and	O
World	B-Application
of	I-Application
Tanks	I-Application
,	O
and	O
encrypted	O
such	O
files	O
.	O
</s>
<s>
Newer	O
variants	O
of	O
TeslaCrypt	B-Application
were	O
not	O
focused	O
on	O
computer	O
games	O
alone	O
but	O
also	O
encrypted	O
Word	O
,	O
PDF	O
,	O
JPEG	O
and	O
other	O
files	O
.	O
</s>
<s>
In	O
all	O
cases	O
,	O
the	O
victim	O
would	O
then	O
be	O
prompted	O
to	O
pay	O
a	O
ransom	O
of	O
$500	O
worth	O
of	O
bitcoins	B-Protocol
in	O
order	O
to	O
obtain	O
the	O
key	O
to	O
decrypt	O
the	O
files	O
.	O
</s>
<s>
Although	O
resembling	O
CryptoLocker	O
in	O
form	O
and	O
function	O
,	O
Teslacrypt	B-Application
shares	O
no	O
code	O
with	O
CryptoLocker	O
and	O
was	O
developed	O
independently	O
.	O
</s>
<s>
The	O
malware	O
infected	O
computers	O
via	O
the	O
Angler	O
Adobe	B-Operating_System
Flash	I-Operating_System
exploit	O
.	O
</s>
<s>
Even	O
though	O
the	O
ransomware	O
claimed	O
TeslaCrypt	B-Application
used	O
asymmetric	O
encryption	O
,	O
researchers	O
from	O
Cisco	O
's	O
Talos	O
Group	O
found	O
that	O
symmetric	O
encryption	O
was	O
used	O
and	O
developed	O
a	O
decryption	O
tool	O
for	O
it	O
.	O
</s>
<s>
This	O
"	O
deficiency	O
"	O
was	O
changed	O
in	O
version	O
2.0	O
,	O
rendering	O
it	O
impossible	O
to	O
decrypt	O
files	O
affected	O
by	O
TeslaCrypt-2.0	O
.	O
</s>
<s>
In	O
May	O
2016	O
,	O
the	O
developers	O
of	O
TeslaCrypt	B-Application
shut	O
down	O
the	O
ransomware	O
and	O
released	O
the	O
master	O
decryption	O
key	O
,	O
thus	O
bringing	O
an	O
end	O
to	O
the	O
ransomware	O
.	O
</s>
