Dameware Mini Remote Control Sends a File Encryption Key as Clear Text
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SecurityTracker Alert ID: 1009557
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CVE Reference: GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Mar 26 2004
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Impact: Disclosure of authentication information, Disclosure of system information, Disclosure of user information
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Exploit Included: Yes
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Version(s): 4.1.0.0
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Description: A vulnerability was reported in Dameware Mini Remote Control. The software transmits an encryption key over the network in clear text.
It is reported that the software sends a Blowfish encryption key over the network without encryption. The 2nd to last string of
16 bytes prior to the file being transferred is reportedly the file encryption key.
It is also reported that the software uses
an insufficiently random generator to create the encryption key, facilitating key cracking attacks.
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Impact: A remote user monitoring the network between the two encryption endpoints can determine the encryption key and gain access to the transmitted file.
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Solution: No solution was available at the time of this entry.
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Vendor URL: www.dameware.com/products/ (Links to External Site)
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Cause: Access control error, Randomization error
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Underlying OS: Windows (NT), Windows (2000), Windows (XP)
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Reported By: ax09001h <ax09001h@hotmail.com>
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Message History:
None.
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Source Message Contents
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Date: 23 Mar 2004 20:17:10 -0000
From: ax09001h <ax09001h@hotmail.com>
Subject: Dameware Passes Weak File Encryption Key in the Clear
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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 compou
nd 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 develope
rs 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 ex
haust the small space of the
Windows’ linear congruential generator (LCG) in rand() to discover the following hypothesized loop f
or 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 c
lear 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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