CVE-2014-9294

Vulnerability

The util/ntp-keygen.c file in the ntp-keygen utility, part of NTP versions prior to 4.2.7p230, uses a weak pseudorandom number generator (PRNG) seed when generating symmetric keys. This flaw makes the resulting keys predictable if an attacker can brute-force the seed space [1][2]. The weak seed is derived from a non-cryptographic source, reducing the effective entropy of the generated keys.

Exploitation

An unauthenticated, remote attacker can exploit this vulnerability by first obtaining a sample of the generated key material (e.g., by capturing NTP packets that use the key for authentication). With the key in hand, the attacker can perform a brute-force search over the limited seed space to recover the seed and subsequently predict future keys or derive the original key [1][3]. No special network position beyond the ability to observe NTP traffic is required.

Impact

Successful exploitation allows the attacker to defeat cryptographic protections that rely on the weak keys. This can lead to disclosure of sensitive information (e.g., NTP authentication credentials), impersonation of legitimate NTP servers, or man-in-the-middle attacks that compromise the integrity and confidentiality of time synchronization data [1][2]. The impact is rated as high (CVSS 7.5) due to the low complexity and network-based attack vector.

Mitigation

The vulnerability is fixed in NTP version 4.2.7p230 and later [1]. Cisco, HP, and Red Hat have released security advisories and patches for their affected products [1][2][3][4]. Users should upgrade to the latest NTP version or apply vendor-specific updates. No workaround is available; upgrading is the only complete mitigation.