Dutch engineers have found a pair of holes in Lotus Development's Notes and Domino's password encryption and the security on public versions of the address list.
User passwords are encrypted as they are entered on both Domino and Notes servers, but the alphanumeric strings (or hashes) to which they are converted can be matched against a master password encryption key and used as a live password by users on the same server, warned Trust Factory B.V., a Netherlands-based security consulting firm, at the Defcon-8 conference in Las Vegas this weekend.
Though cracking an organization's system in this way would require a pretty high level of sophistication for one of the holes, Web-based systems are particularly vulnerable, the Trust Factory warning said.
Trust Factory engineer Patrick Guenther was able to crack Notes to gain access to passwords and individual files, which he demonstrated at the conference in a joint presentation with Secure Design International Group (SDI).
"I wouldn't describe it as minor. I think that the implications are rather large, based on the way that Notes [servers] are configured at most organizations," said Matthew Devost, one of the presenters for SDI.
He said Notes administrators can protect their databases simply by "salting" hashes -- adding a random number into the scrambled alphanumeric string that represents a password. This function is an option built into newer versions of both Domino and Notes.
Devost said a cracker can access the hashes with a few commands through a Web browser if the address list is publicly available there.
Another way to break the hashings is through a brute-force attack using macros, viruses or other code designed to grab the recipient's personal information, including the encrypted passwords, and sending them back to the author of the code. Even salted hashes could be sent back to a cracker in this way, Devost said.
"All it takes is one person to run a Word document," he said.
Domino product managers Kevin Lynch and Katherine Spanbauer said Lotus has advised users of these vulnerabilities for some time, and urged administrators to use the salted encryption. However, some systems need the unsalted version to remain backwards-compatible in a mixed shop.
"Simply use the other hash that's been available since [Notes version] 4.6 and you will no longer be able to perpetrate that attack," Lynch said.
"It's an extremely sophisticated style of attack and the attacker would have to already have internal access to resources," Spanbauer said. The attacker would also need special software to decipher the hash, then place it where the password is normally stored in memory.
That technique is only valid if the user has the same password for Web and server access. Most users access the server through Notes, not the Web, Spanbauer said.
Trust Factory and SDI suggest taking the following steps to protect your Notes database:
- Restrict access from the Web
- Choose different passwords for ID and HTTP accounts - Store user ID files on removable media - Use strong password hashing - Manually upgrade to the stronger hash