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Dameware Mini Remote Control version 4.1.0.0 and presumably other 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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