<s>
In	O
computing	O
,	O
ACE	B-General_Concept
is	O
a	O
proprietary	O
data	B-General_Concept
compression	I-General_Concept
archive	O
file	O
format	O
developed	O
by	O
Marcel	O
Lemke	O
,	O
and	O
later	O
bought	O
by	O
e-merge	O
GmbH	O
.	O
</s>
<s>
WinAce	B-Application
,	O
maintained	O
by	O
e-merge	O
GmbH	O
,	O
is	O
used	O
to	O
compress	O
and	O
decompress	O
ACE	B-General_Concept
files	O
under	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
When	O
installed	O
,	O
it	O
lets	O
the	O
user	O
choose	O
between	O
paying	O
for	O
a	O
registration	O
or	O
installing	O
WhenU	B-Application
SaveNow	I-Application
adware	O
.	O
</s>
<s>
e-merge	O
GmbH	O
also	O
produces	O
a	O
Commandline	B-Application
ACE	I-Application
for	O
DOS	O
;	O
and	O
a	O
freeware	O
command-line	B-Application
interface	I-Application
decompression	O
tool	O
for	O
Linux	B-Application
(	O
i386	B-General_Concept
)	O
and	O
macOS	B-Application
called	O
"	O
Unace	O
"	O
.	O
</s>
<s>
None	O
of	O
the	O
above	O
is	O
open	B-License
source	I-License
free	B-Application
software	I-Application
.	O
</s>
<s>
On	O
November	O
23	O
,	O
2007	O
,	O
version	O
2.69	O
of	O
WinACE	B-Application
was	O
released	O
,	O
including	O
a	O
less-intrusive	O
adware	O
application	O
,	O
MeMedia	O
AdVantage	O
,	O
which	O
replaces	O
WhenU	B-Application
.	O
</s>
<s>
An	O
older	O
version	O
of	O
an	O
Unace	O
1.2b	O
is	O
free	B-Application
software	I-Application
and	O
licensed	O
under	O
the	O
GPL	B-License
by	O
the	O
author	O
Marcel	O
Lemke	O
,	O
but	O
it	O
cannot	O
extract	O
ACE	B-General_Concept
archives	O
from	O
version	O
2.0	O
and	O
newer	O
.	O
</s>
<s>
A	O
newer	O
version	O
of	O
Unace	O
2.5	O
that	O
supports	O
ACE	B-General_Concept
2.0	O
archives	O
is	O
available	O
under	O
a	O
restrictive	O
source	B-License
available	I-License
license	I-License
,	O
also	O
by	O
Marcel	O
Lemke	O
.	O
</s>
<s>
It	O
is	O
limited	O
to	O
unpacking	O
ACE	B-General_Concept
1.0	O
archives	O
.	O
</s>
<s>
Since	O
2017	O
,	O
there	O
is	O
a	O
BSD	B-Operating_System
licensed	I-Operating_System
python	O
module	O
and	O
CLI	O
utility	O
by	O
Daniel	O
Roethlisberger	O
,	O
that	O
supports	O
unpacking	O
of	O
ACE	B-General_Concept
2.0	O
format	O
archives	O
.	O
</s>
<s>
Packing	O
of	O
ACE	B-General_Concept
files	O
is	O
licensed	O
as	O
proprietary	O
information	O
and	O
only	O
available	O
through	O
WinACE	B-Application
,	O
while	O
unpacking	O
of	O
ACE	B-General_Concept
files	O
is	O
supported	O
by	O
a	O
number	O
of	O
third-party	O
archivers	O
.	O
</s>
<s>
However	O
,	O
virtually	O
all	O
of	O
them	O
(	O
the	O
ones	O
that	O
support	O
ACE	B-General_Concept
2.x	O
format	O
)	O
do	O
this	O
by	O
using	O
the	O
proprietary	O
"	O
unace.dll	O
"	O
from	O
e-merge	O
GmbH	O
.	O
</s>
<s>
Since	O
at	O
least	O
2015	O
,	O
ACE	B-General_Concept
archives	O
have	O
been	O
used	O
to	O
deliver	O
malware	O
to	O
victims	O
by	O
e-mail	O
.	O
</s>
<s>
This	O
tactic	O
was	O
viable	O
because	O
popular	O
archiving	O
software	O
was	O
able	O
to	O
uncompress	O
ACE	B-General_Concept
archives	O
,	O
but	O
support	O
for	O
the	O
ACE	B-General_Concept
format	O
in	O
security	O
products	O
such	O
as	O
mail	O
filters	O
,	O
web	O
content	O
filters	O
and	O
anti-virus	O
software	O
was	O
generally	O
weak	O
.	O
</s>
<s>
In	O
February	O
2019	O
several	O
major	O
security	O
vulnerabilities	O
were	O
found	O
in	O
the	O
unacev2.dll	O
library	O
which	O
is	O
used	O
by	O
WinRAR	B-Application
and	O
other	O
archiving	O
products	O
.	O
</s>
<s>
Since	O
WinACE	B-Application
is	O
abandonware	O
,	O
users	O
are	O
advised	O
against	O
opening	O
ACE	B-General_Concept
archives	O
in	O
WinRAR	B-Application
and	O
possibly	O
other	O
products	O
using	O
this	O
library	O
.	O
</s>
<s>
WinRAR	B-Application
stopped	O
supporting	O
ACE	B-General_Concept
as	O
of	O
version	O
5.70	O
,	O
and	O
similar	O
products	O
are	O
following	O
suit	O
.	O
</s>
