CVE-2018-6653

Vulnerability

CVE-2018-6653 affects the comforte SWAP software across versions 1049 through 1069 and 20.0.0 through 21.5.3 (as used in SSLOBJ on HPE NonStop SSL T0910, and in comforte SecurCS, SecurFTP, SecurLib/SSL-AT, and SecurTN products). After executing the RELOAD CERTIFICATES command, the set of cipher suites in use changes to include all cipher suites the program supports, including those with a null cipher. This allows clients to connect with a weak cipher suite, potentially exposing sensitive data. The condition persists until the SWAP process is restarted [1].

Exploitation

An attacker on the network path can exploit this vulnerability by connecting to the SSL/TLS server after a RELOAD CERTIFICATES command has been executed. The attacker can request the server negotiate a weak cipher suite (e.g., RC4-MD5). If successful, the server will accept the weak cipher, as the reload command has expanded the acceptable cipher list to include all supported suites. No authentication or special privileges are required beyond network access to sniff traffic [1].

Impact

Successful exploitation allows a remote attacker to defeat intended cryptographic protection mechanisms by downgrading to a weak or null cipher suite. This compromises the confidentiality of data transmitted between the client and server, as an attacker who can sniff network traffic may be able to decrypt the communication. The integrity of the data stream may also be weakened, depending on the cipher selected [1].

Mitigation

The vulnerability is fixed in SWAP version 21.6.0, which is available for download from the comforte website. Users must update to 21.6.0 to remediate the issue. As a workaround, the SWAP process should be restarted after executing a RELOAD CERTIFICATES command to restore the configured cipher suite set. No other mitigation is described in the available references [1].