CVE-2020-8936 is a vulnerability in Google Asylo
Published on December 15, 2020
Arbitrary enclave memory overwrite vulnerability in ECall ecall_restore
An arbitrary memory overwrite vulnerability in Asylo versions up to 0.6.0 allows an attacker to make a host call to UntrustedCall. UntrustedCall failed to validate the buffer range within sgx_params and allowed the host to return a pointer that was an address within the enclave memory. This allowed an attacker to read memory values from within the enclave.
Vulnerability Analysis
CVE-2020-8936 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and no impact on availability.
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Products Associated with CVE-2020-8936
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Affected Versions
Google LLC Asylo:- Version 0.6.0, <= 0.6.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.