full-disclosure - Dameware Passes Weak File Encryption Key in the Clear

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Message-ID: <BAY13-F728zjx4NOPk00001306c@hotmail.com>
From: ax09001h at hotmail.com (ax09001h ax09001h)
Subject: Dameware Passes Weak File Encryption Key in the Clear

Dameware Mini Remote Control version 4.1.0.0 and presumably previous 
versions pass a Blowfish encryption key over the wire in the clear.  It is 
bad enough that they appear to be using Blowfish in Electronic Codebook 
Mode; but they compound their errors by the following two vulnerabilities.

The Dameware Mini Remote Control offers the capability to transfer files 
between the host and client encrypted using 128-bit Blowfish Encryption.  
Their first mistake is using a poor random bit generator to create their 
encryption key.  After identifying the key in the clear I was able to 
surmise that the lack of cryptographic expertise of the Dameware developers 
was systemic and checked to see if they were using the built-in rand() 
function to generate the key.  It did not take long to exhaust the small 
space of the Windows’ linear congruential generator (LCG) in rand() to 
discover the following hypothesized loop for generating their file 
encryption key.

int 			i;
unsigned char 	dw_f_key[16];
srand(time(NULL));
for(i=0;i<16;i++){
	dw_f_key[i] = rand();
}

The second major and more serious mistake is that they actually pass the 
file encryption key in the clear over the wire.  This can be seen by 
analyzing packets between host and target.  In a packet just prior to the 
file being sent the second to the last string of 16-bytes is the file 
encryption key.

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