CVE-2017-3738

Publication date 7 December 2017

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

5.9 · Medium

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
openssl 19.04 disco
Fixed 1.1.0g-2ubuntu3
18.10 cosmic
Fixed 1.1.0g-2ubuntu3
18.04 LTS bionic
Fixed 1.1.0g-2ubuntu3
17.10 artful
Fixed 1.0.2g-1ubuntu13.3
17.04 zesty
Fixed 1.0.2g-1ubuntu11.4
16.04 LTS xenial
Fixed 1.0.2g-1ubuntu4.10
14.04 LTS trusty
Not affected
openssl098 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
openssl1.0 19.04 disco Not in release
18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
17.10 artful Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release

Notes

leosilva

"This only affects processors that support the AVX2 but not ADX extensions like Intel Haswell (4th generation)."

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
openssl

Severity score breakdown

Parameter Value
Base score 5.9 · Medium
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact None
Availability impact None
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N