CVE-2017-12173
Description
It was found that sssd's sysdb_search_user_by_upn_res() function did not sanitize requests when querying its local cache and was vulnerable to injection. In a centralized login environment, if a password hash was locally cached for a given user, an authenticated attacker could use this flaw to retrieve it.
Statement
This issue affects the versions of sssd as shipped with Red Hat Satellite version 6.0. More recent versions of Satellite no longer ships sssd. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Mitigation
It is possible to disable manually credential caching :
* Stop the sssd service
* Delete the cache (rm -f /var/lib/sss/db/* /var/log/sssd/*) or manually remove the hashes for the database
* In the sssd configuration file, change cache_credentials to False for each domains
* start the sssd service again
However, tools such as realmd & ipa-client-install might enable credential caching, and should be used with care.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | 8.8 | 4.3 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | High | Low |
| Integrity Impact | None | High | None |
| Availability Impact | None | High | None |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
An attacker could provide unexpected values and cause a program crash or arbitrary control of resource allocation, leading to excessive consumption of resources such as memory and CPU.
Confidentiality
Technical Impact: Read Memory; Read Files or Directories
An attacker could read confidential data if they are able to control resource references.
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.
Acknowledgements
This issue was discovered by Sumit Bose (Red Hat).
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