Researchers have discovered new variations of the Spectre attack and they received $100,000 from Intel through the company’s bug bounty program.
The new flaws are variations of Spectre Variant 1 (CVE-2017-5753) and they are tracked as Spectre 1.1 (CVE-2018-3693) and Spectre 1.2.
The more serious of these issues is Spectre 1.1, which has been described as a bounds check bypass store (BCBS) issue.
“[Spectre1.1 is] a new Spectre-v1 variant that leverages speculative stores to create speculative buffer overflows,” researchers Vladimir Kiriansky of MIT and Carl Waldspurger of Carl Waldspurger Consulting explained in a paper.
“Much like classic buffer overflows, speculative out-of-bounds stores can modify data and code pointers. Data-value attacks can bypass some Spectre-v1 mitigations, either directly or by redirecting control flow. Control-flow attacks enable arbitrary speculative code execution, which can bypass fence instructions and all other software mitigations for previous speculative-execution attacks. It is easy to construct return-oriented-programming (ROP) gadgets that can be used to build alternative attack payloads,” they added.
Spectre 1.2 impacts CPUs that fail to enforce read/write protections, allowing an attacker to overwrite read-only data and code pointers in an effort to breach sandboxes, the experts said.
Microsoft also updated its Spectre/Meltdown advisories on Tuesday to include information on CVE-2018-3693.
“We are not currently aware of any instances of BCBS in our software, but we are continuing to research this vulnerability class and will work with industry partners to release mitigations as required,” the company said.
Oracle is also assessing the impact of these vulnerabilities on its products and has promised to provide technical mitigations.
“Note that many industry experts anticipate that a number of new variants of exploits leveraging these known flaws in modern processor designs will continue to be disclosed for the foreseeable future,” noted Eric Maurice, Director of Security Assurance at Oracle. “These issues are likely to primarily impact operating systems and virtualization platforms, and may require software update, microcode update, or both. Fortunately, the conditions of exploitation for these issues remain similar: malicious exploitation requires the attackers to first obtain the privileges required to install and execute malicious code against the targeted systems.”
Just as the researchers published their paper, Intel made a $100,000 payment to Kiriansky via the company’s HackerOne bug bounty program. The experts did reveal in their paper that the research was partially sponsored by Intel.
Following the disclosure of the Spectre and Meltdown vulnerabilities in January, Intel announced a bug bounty program for side-channel exploits with rewards of up to $250,000 for issues similar to Meltdown and Spectre. The reward for flaws classified “high severity” can be as high as $100,000.