The report shows only 18% of energy companies could identify high-value security assets and business processes for better protection.
A majority (74%) of the 186 oil and gas company leaders surveyed in Accenture's High Performance Security 2016 Report said their organisation was confident that cybersecurity measures will yield valuable results.
More than three-quarters believe their top strategies are now able to protect their companies' reputations, information and prevent service disruption.
However, this is at odds with 60% of energy leaders who said cybersecurity is a "bit of a black box", as they don't quite understand the timing or impact of cyberattacks.
When asked about basic requirements to keep their company secure, energy leaders were less confident than their counterparts in other industries in their ability to measure the impact of breaches (40% compared to 47% for the cross-industry average) and to know their frequency (28% compared to 41%).
Oil and gas company leaders reported an average of 96 cyberattacks over 12 months, with one in three succeeding in a breach that was discovered only 62% of the time by firms' security teams.
Even then, detection took months for 51% of companies and weeks for 25%.
The rest of the time, other employees and law enforcement officials most often discovered the breaches.
Oil and gas companies don't have far to look to identify the sources of most cyberattacks.
Company leaders said breaches are mostly from malicious company insiders (43%) or staff who accidentally published information (23%).
External hackers accounted for 21% of attacks.
"Security does not end at the edge of the corporate network. It includes both operational technology and back office systems across the oil and gas value chain," Accenture's resources security boss Jim Guinn said.
"Protecting core operations requires better investments in cyber defence including network analytics, cyber incident management programs that include both OT and IT networks, and ongoing testing to help identify any gaps.
"With a more comprehensive cybersecurity strategy that includes assets across the entire organisation, oil and gas companies can be better prepared when a cyber event occurs."
Executives identified the top effective tools for responding to cyberattacks as internal cross-functional teams (41%), standard operating procedures (37%), established technologies (36%) and communications plans (34%).
Not surprisingly, with the rise of the Industrial Internet of Things and the convergence of operational technology and information technology, respondents cited the need to fill cybersecurity gaps in end point/network security as their most pressing concern (55%).
They expressed low confidence (18%) in identifying high-value security assets and business processes needed for better protection, and only 24% were confident of their capabilities in cyberattack scenarios.
The results of this survey were analysed in collaboration with Oxford Economics to develop the Accenture Security Index comparing the relative strength of organisations to protect themselves from cyberattacks.
To gauge the effectiveness of current enterprise security efforts and the adequacy of their existing investments, Accenture surveyed 2000 top enterprise security practitioners representing companies with annual revenues of $1 billion or more.
According to the recently released Accenture Security Index, oil and gas organisations ranked second to last among cross-industry evaluation of high-performance cybersecurity capabilities with an overall ranking of 27%, meaning these organisations exhibited high performance in only nine capabilities on average.
Additionally, oil and gas organisations ranked last in all industries in the threat vector monitoring capability (22%).
