BlackBerry issued a security advisory Tuesday to address a vulnerability that could enable an attacker to impersonate a legitimate user on a local machine or network.
According to BlackBerry, a vulnerability exists in the implementation of the logging of exceptions encountered during user or session management in BlackBerry Enterprise Service 10, standalone Universal Device Service and BlackBerry Enterprise Server 5.0.4 versions. So far, the company is not aware of any attacks targeting the issue.
“During rare cases of an exception, certain credentials are logged in plain text. For BlackBerry Enterprise Server 5, these credentials include shared secrets that are used between the Enterprise Instant Messenger server and device clients to encrypt enterprise instant messages,” according to the company. “For BlackBerry Enterprise Service 10 and Universal Device Service 6, they consist of shared secrets and domain credentials. Typically, only the system administrator would have access to the affected diagnostic logs.”
A successful attack would require a hacker gain access to both the server and certain diagnostic logs through either a valid logon or an unrelated compromise of the server, mitigating the attack somewhat. If the attacker is able to gain access to the exception logs – either directly, through an unencrypted backup of the server or via an adjacent network if the directory is shared – the attacker could obtain logged shared secrets and use them to remove encryption on Enterprise Instant Messenger messages.
In order to remove that encryption however, the attacker must also gain access to messages, which would require an additional man-in-the-middle attack, according to the company.
“This issue is mitigated for all customers by the prerequisite that the attacker must gain access to the affected diagnostic logs,” the advisory notes. “Typically, only the system administrator would have this access. The credentials are only logged in an error case and most server installations are unlikely to have this information logged. An attacker is not able to remotely trigger this error case and so would have no way to force the creation of the exception log.”
To protect themselves, BlackBerry recommends customers install the related software update and redact or delete existing logs.