SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-3738

There is an overflow bug in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli.

MEDIUM 5.9EPSS 13.4%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 13.4%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.

Description

There is an overflow bug in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH1024 are considered just feasible, because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH1024 private key among multiple clients, which is no longer an option since CVE-2016-0701. This only affects processors that support the AVX2 but not ADX extensions like Intel Haswell (4th generation). Note: The impact from this issue is similar to CVE-2017-3736, CVE-2017-3732 and CVE-2015-3193. OpenSSL version 1.0.2-1.0.2m and 1.1.0-1.1.0g are affected. Fixed in OpenSSL 1.0.2n. Due to the low severity of this issue we are not issuing a new release of OpenSSL 1.1.0 at this time. The fix will be included in OpenSSL 1.1.0h when it becomes available. The fix is also available in commit e502cc86d in the OpenSSL git repository.

CVSS 3.1
5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
13.41% probability · 96th percentile
CISA KEV
Not listed
Weakness
CWE-200
Affected
openssl/openssl · debian/debian linux · nodejs/node.js
Source
openssl-security@openssl.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.