- Attack Vector: Network
- The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
- Attack Complexity: High
- The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
- Attack Requirements: Present
- The successful attack depends on the presence of specific deployment and execution conditions of the vulnerable system that enable the attack. These include: a race condition must be won to successfully exploit the vulnerability (the successfulness of the attack is conditioned on execution conditions that are not under full control of the attacker, or the attack may need to be launched multiple times against a single target before being successful); the attacker must inject themselves into the logical network path between the target and the resource requested by the victim (e.g. vulnerabilities requiring an on-path attacker).
- Privileges Required: None
- The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
- User Interaction: None
- The vulnerable system can be exploited without interaction from any human user, other than the attacker.
- Vulnerable system confidentiality: High
- There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
- Vulnerable system integrity: High
- There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
- Vulnerable system availability: Low
- Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
- Subsequent system confidentiality: High
- There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
- Subsequent system integrity: High
- There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the Subsequent System. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the Subsequent System.
- Subsequent system availability: Low
- Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Subsequent System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Subsequent System.
- Recovery: User
- The system requires manual intervention by the user to recover services, after an attack has been performed.
- Value Density: Concentrated
- The vulnerable system is rich in resources. Heuristically, such systems are often the direct responsibility of “system operators” rather than users. An example of Concentrated (think: broad) Value Density would be an attack on a central email server.
- Vulnerability Response Effort: High
- The actions required to respond to a vulnerability are significant and/or difficult, and may possibly lead to an extended, scheduled service impact. This would need to be considered for scheduling purposes including honoring any embargo on deployment of the selected response. Alternatively, response to the vulnerability in the field is not possible remotely. The only resolution to the vulnerability involves physical replacement (e.g. units deployed would have to be recalled for a depot level repair or replacement). Examples include: a highly privileged driver update, microcode or UEFI BIOS updates, or software upgrades requiring careful analysis and understanding of any potential infrastructure impact before implementation. A UEFI BIOS update that impacts Trusted Platform Module (TPM) attestation without impacting disk encryption software such as Bit locker is a good recent example. Irreparable failures such as non-bootable flash subsystems, failed disks or solid-state drives (SSD), bad memory modules, network devices, or other non-recoverable under warranty hardware, should also be scored as having a High effort.
- Provider Urgency: Red
- Provider has assessed the impact of this vulnerability as having the highest urgency.
Definitions: FIRST CVSS v4.0 specification.