# Vulnerability Assessment of Sensor Systems
## 4 Validation of the Sensor System Vulnerability Assessment Method
The examples of the considered vulnerabilities are:  
* incompatibilities between specific software solutions of sensors and systems of the higher level (host-based) supervising sensors,
* incompatibilities between specific software solutions of sensors and IT cyber security solutions (COTS),
* constrained power and computation resources of sensors faced with time-critical operations implying the use of simplified communication protocols and cryptographic techniques,
* no security domain, no privilege separation,
* vulnerabilities related to wireless devices,
* insecure network architecture,
* enabled trap doors to unauthorized users,
* hardware vulnerabilities [56]. Examples of considered attacks are:  
* manipulation of sensor output data,
* Denial of Service--causing system unavailability and breaching time-critical operation,
* forging data designed for the sensor actuator (if any applied in a sensor),
* buffer overflow,
* SQL injection,
* attacks on different layers of the communication stack,
* advanced physical security invasive attacks on hardware, e.g., tampering, probing, voltage/temperature/radiation imprinting, clock glitching, changing environment conditions [56],
* advanced physical security noninvasive attacks on hardware, e.g., simple/differential power analysis (SPA/DPA) or electromagnetic emanations analysis (EMA) [56]. The second EEP2-2 output is placed into the _AttackScenario_AS_ knowledge base. The _AttackScenario_AS_ ontology class expresses all identified, possible attack scenarios relevant to the given TOE. The individuals of the _PotentialVulnerability_PV_ and _AttackScenario_AS_ classes are identified concurrently in EEP2-2 and they are closely related, which is expressed by the object properties: _relatedAttackScenario_ and _attackDealsWith_PV_. The attack scenarios are expressed by two data properties (Figure 5), extending information included in the potential vulnerability description:  
* _AttackDescription_--supplementary description of a scenario,
* _AttackProvenance_--such as the name of the source which provides information. The third EEP2-2 output related to the ApplicableVulnerability_AV knowledge base concerns only AVA_VAN.1 evaluation. It will be discussed in Case 3, where it is very important. Figure 4: Potential vulnerability presented in the Protege tool. Figure 5: Attack scenario presented in the Protege tool. Case 3 Performing Independent Focused Vulnerability Analysis of the TOE Using the Guidance Documentation, Functional Specification, TOE Design, Security Architecture, Description (and Implementation Representation) to Identify Potential Vulnerabilities in the TOE (AVA_VANx.3E, x = 2,3,4)  
For AVA_VAN.2 and higher, the evaluators should identify potential vulnerabilities introduced by the developers. For this reason, evaluation evidences are analyzed with respect to potential vulnerabilities, mainly: ASE (security target), ADV_TDS (design--TOE decomposition to subsystems and modules), ADV_FSP (functional specification--interfaces), ADV_IMP (implementation--source code, electronic schemes), ADV_ARC (architecture--how the architecture is applied to protect security functions), AGD_PRE (preparative user guide), and AGD_OPE (operational user guide). Similarly to EEP2-1/EEP2-2, the work embraces two steps:  
* planning--deals with \"EEP3-1 areas of concern identification\",
* execution--deals with \"EEP3-2 vulnerability analysis based on evidences\". As mentioned above, the areas of concern are understood as the suspected, vulnerability-prone parts of the TOE design. Their identification allows orientation of the detailed analysis of evaluation evidences. The _AreaOfConcern_AOC_ ontology class is shown in Figure 6. It has two data properties:  
* _complexSolution_--e.g., excessively complicated solutions, not well structured areas of the design, areas with too many patches, etc.,
* _vulnerabArea_--e.g., unproven applied technologies, vulnerability-prone technologies, etc. EEP3-1 concerns the preparation of evidence analysis and involves two activities:  
1.