An OpenSSL vulnerability has been found in ScreenOS. The ASN.1 buffered I/O functions in OpenSSL before 0.9.8v do not properly interpret integer data, which allows remote attackers to conduct buffer overflow attacks, and cause a denial of service (memory corruption) via crafted DER data, as demonstrated by an X.509 certificate or an RSA public key. This vulnerability is an issue when using the following features in ScreenOS: 1. HTTPS for ScreenOS management. 2. WebAuth with SSL is enabled. 3. IPSec VPN with certificates (not a preshared key). If any of the above is in use you may be exposed to the vulnerability. Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Software updates to ScreenOS have been released to resolve this issue. Releases containing the fix include ScreenOS: 5.4.0r27, 6.2.0r16, and 6.3.0r13. KB16765 [juniper.net] - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
How to obtain fixed software: Software release Service Packages are available at http://support.juniper.net from the "Download Software" links. Select "ScreenOS" and choose the version applicable to your environment and installation.
1. If HTTPS is enabled for ScreenOS management, you could move to SSH management until you can upgrade. 2. Disable the use of WebAuth if you have it enabled but do not need to use it. 3. Limit the IPSec peer addresses to specific known hosts. 4. Limit the source addresses that can access the HTTPS management interface.