Upstream information

CVE-2021-3634 at MITRE

Description

A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating "secret_hash" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having moderate severity.

CVSS v2 Scores
  National Vulnerability Database
Base Score 4
Vector AV:N/AC:L/Au:S/C:N/I:N/A:P
Access Vector Network
Access Complexity Low
Authentication Single
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial
CVSS v3 Scores
  National Vulnerability Database SUSE
Base Score 6.5 3.5
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Access Vector Network Network
Access Complexity Low Low
Privileges Required Low Low
User Interaction None Required
Scope Unchanged Unchanged
Confidentiality Impact None None
Integrity Impact None None
Availability Impact High Low
CVSSv3 Version 3.1 3.1
SUSE Bugzilla entries: 1189608 [RESOLVED / FIXED], 1194948 [NEW]

No SUSE Security Announcements cross referenced.

List of released packages

Product(s) Fixed package version(s) References
SUSE Linux Enterprise Desktop 15 SP4
SUSE Linux Enterprise High Performance Computing 15 SP4
SUSE Linux Enterprise Module for Basesystem 15 SP4
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server for SAP Applications 15 SP4
SUSE Manager Proxy 4.3
SUSE Manager Retail Branch Server 4.3
SUSE Manager Server 4.3
  • libssh-config >= 0.9.6-150400.1.5
  • libssh-devel >= 0.9.6-150400.1.5
  • libssh4 >= 0.9.6-150400.1.5
  • libssh4-32bit >= 0.9.6-150400.1.5
 Patchnames:
SUSE Linux Enterprise Module for Basesystem 15 SP4 GA libssh-config-0.9.6-150400.1.5
openSUSE Leap 15.4
  • libssh-config >= 0.9.6-150400.1.5
  • libssh4 >= 0.9.6-150400.1.5
  • libssh4-32bit >= 0.9.6-150400.1.5
 Patchnames:
openSUSE Leap 15.4 GA libssh-config-0.9.6-150400.1.5
openSUSE Tumbleweed
  • libssh-config >= 0.9.6-1.2
  • libssh-devel >= 0.9.6-1.2
  • libssh4 >= 0.9.6-1.2
  • libssh4-32bit >= 0.9.6-1.2
 Patchnames:
openSUSE Tumbleweed GA libssh-config-0.9.6-1.2

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification.

Product(s) Source package State
SUSE CaaS Platform 4.0 libssh Not affected
SUSE CaaS Platform 4.5 libssh Not affected
SUSE Enterprise Storage 6 libssh Not affected
SUSE Enterprise Storage 7 libssh Not affected
SUSE Linux Enterprise Desktop 15 SP2 libssh Not affected
SUSE Linux Enterprise Desktop 15 SP3 libssh Not affected
SUSE Linux Enterprise High Performance Computing 12 SP5 libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 LTSS libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP1 ESPOS libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP1 LTSS libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2 libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2 ESPOS libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2 LTSS libssh Not affected
SUSE Linux Enterprise High Performance Computing 15 SP3 libssh Not affected
SUSE Linux Enterprise Micro 5.0 libssh Not affected
SUSE Linux Enterprise Micro 5.1 libssh Not affected
SUSE Linux Enterprise Module for Basesystem 15 SP2 libssh Not affected
SUSE Linux Enterprise Module for Basesystem 15 SP3 libssh Not affected
SUSE Linux Enterprise Server 12 SP4 ESPOS libssh Not affected
SUSE Linux Enterprise Server 12 SP4 LTSS libssh Not affected
SUSE Linux Enterprise Server 12 SP5 libssh Not affected
SUSE Linux Enterprise Server 15 ESPOS libssh Not affected
SUSE Linux Enterprise Server 15 LTSS libssh Not affected
SUSE Linux Enterprise Server 15 SP1 LTSS libssh Not affected
SUSE Linux Enterprise Server 15 SP2 libssh Not affected
SUSE Linux Enterprise Server 15 SP2 LTSS libssh Not affected
SUSE Linux Enterprise Server 15 SP3 libssh Not affected
SUSE Linux Enterprise Server Business Critical Linux 15 SP1 libssh Not affected
SUSE Linux Enterprise Server Business Critical Linux 15 SP2 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP4 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP5 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 15 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP1 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP2 libssh Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP3 libssh Not affected
SUSE Linux Enterprise Storage 7 libssh Not affected
SUSE Linux Enterprise Storage 7.1 libssh Not affected
SUSE Manager Proxy 4.0 libssh Analysis
SUSE Manager Proxy 4.1 libssh Not affected
SUSE Manager Proxy 4.2 libssh Not affected
SUSE Manager Retail Branch Server 4.0 libssh Analysis
SUSE Manager Retail Branch Server 4.1 libssh Not affected
SUSE Manager Retail Branch Server 4.2 libssh Not affected
SUSE Manager Server 4.0 libssh Analysis
SUSE Manager Server 4.1 libssh Not affected
SUSE Manager Server 4.2 libssh Not affected
SUSE OpenStack Cloud 9 libssh Not affected
SUSE OpenStack Cloud Crowbar 9 libssh Not affected