<s>
Alabama	B-Application
is	O
a	O
computer	O
virus	O
,	O
discovered	O
in	O
October	O
1989	O
on	O
the	O
campus	O
of	O
the	O
Hebrew	O
University	O
of	O
Jerusalem	B-Application
.	O
</s>
<s>
Alabama	B-Application
is	O
a	O
fairly	O
standard	O
file	O
infector	O
outside	O
its	O
odd	O
behaviour	O
of	O
deciding	O
what	O
files	O
to	O
infect	O
.	O
</s>
<s>
When	O
an	O
infected	O
file	O
is	O
executed	O
,	O
Alabama	B-Application
goes	O
memory	O
resident	O
.	O
</s>
<s>
Whenever	O
a	O
.EXE	O
file	O
is	O
executed	O
from	O
this	O
point	O
on	O
,	O
Alabama	B-Application
will	O
search	O
out	O
for	O
another	O
file	O
to	O
infect	O
.	O
</s>
<s>
Files	O
infected	O
by	O
Alabama	B-Application
increase	O
in	O
size	O
by	O
1,560	O
bytes	O
.	O
</s>
<s>
A	O
number	O
of	O
symptoms	O
are	O
associated	O
with	O
Alabama	B-Application
:	O
</s>
<s>
On	O
Fridays	O
,	O
Alabama	B-Application
will	O
begin	O
to	O
modify	O
the	O
File	B-Application
Allocation	I-Application
Table	I-Application
.	O
</s>
<s>
One	O
hour	O
after	O
an	O
infected	O
program	O
is	O
run	O
,	O
Alabama	B-Application
will	O
bring	O
up	O
a	O
flashing	O
box	O
with	O
the	O
text	O
"	O
SOFTWARE	O
COPIES	O
PROHIBITED	O
BY	O
INTERNATIONAL	O
LAW	O
..............	O
Box	O
1055	O
Tuscambia	O
ALABAMA	B-Application
USA.	O
"	O
</s>
<s>
The	O
third	O
symptom	O
is	O
by	O
far	O
the	O
clearest	O
indication	O
of	O
an	O
Alabama	B-Application
infection	O
.	O
</s>
<s>
However	O
,	O
the	O
implication	O
of	O
the	O
message	O
is	O
that	O
Alabama	B-Application
was	O
released	O
in	O
an	O
attempt	O
to	O
curb	O
software	O
piracy	O
.	O
</s>
<s>
This	O
message	O
also	O
suggests	O
that	O
the	O
PO	O
Box	O
may	O
very	O
well	O
not	O
belong	O
to	O
the	O
author	O
:	O
the	O
author	O
clearly	O
meant	O
Tuscumbia	O
,	O
Alabama	B-Application
,	O
as	O
Tuscambia	O
is	O
not	O
a	O
city	O
.	O
</s>
<s>
On	O
Fridays	O
,	O
Alabama	B-Application
will	O
begin	O
to	O
modify	O
the	O
File	B-Application
Allocation	I-Application
Table	I-Application
in	O
an	O
odd	O
way	O
.	O
</s>
<s>
Instead	O
of	O
searching	O
for	O
a	O
file	O
to	O
infect	O
,	O
Alabama	B-Application
searches	O
for	O
a	O
file	O
to	O
cross-reference	O
.	O
</s>
<s>
For	O
instance	O
,	O
on	O
a	O
machine	O
where	O
Alabama	B-Application
is	O
resident	O
,	O
executing	O
PROGRAM1.EXE	O
on	O
a	O
Friday	O
may	O
cause	O
the	O
virus	O
to	O
search	O
for	O
another	O
program	O
and	O
find	O
PROGRAM2.EXE	O
.	O
</s>
<s>
Alabama	B-Application
will	O
then	O
modify	O
the	O
FAT	O
so	O
that	O
whenever	O
PROGRAM1.EXE	O
is	O
executed	O
,	O
PROGRAM2.EXE	O
displays	O
instead	O
.	O
</s>
<s>
The	O
WildList	O
,	O
an	O
organisation	O
tracking	O
computer	O
viruses	O
,	O
never	O
reported	O
Alabama	B-Application
as	O
being	O
in	O
the	O
field	O
.	O
</s>
<s>
Since	O
the	O
advent	O
of	O
Windows	B-Application
,	O
even	O
successful	O
DOS	B-Device
viruses	O
have	O
become	O
increasingly	O
rare	O
.	O
</s>
<s>
As	O
such	O
,	O
Alabama	B-Application
can	O
be	O
considered	O
obsolete	O
.	O
</s>
<s>
There	O
is	O
one	O
known	O
variant	O
of	O
Alabama	B-Application
.	O
</s>
<s>
Alabama.B	O
was	O
distributed	O
as	O
a	O
modified	O
SDIR.COM	O
.	O
</s>
<s>
SDIR.COM	O
was	O
a	O
program	O
created	O
to	O
replace	O
the	O
DOS	B-Device
DIR	B-Device
command	O
.	O
</s>
<s>
Like	O
the	O
original	O
Alabama	B-Application
,	O
the	O
"	O
B	O
"	O
variant	O
does	O
not	O
infect	O
.COM	O
files	O
.	O
</s>
