CVE-2018-8778
Description
A integer underflow was found in the way String#unpack decodes the unpacking format. An attacker, able to control the unpack format, could use this flaw to disclose arbitrary parts of the application's memory.
Statement
This issue affects the versions of ruby as shipped with Red Hat CloudForms 4. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
This issue affects the versions of ruby as shipped with Red Hat Subscription Asset Manager 1. Red Hat Product Security has rated this issue as having security impact of Moderate. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
Mitigation
Vulnerable code when String#unpack's argument is attacker controlled.
In the unpack format string argemument, manual sanitization can be done by preventing the number following '@' to overflow to a negative number. See https://dev.to/sqreenio/an-in-depth-look-at-cve-2018-8878-or-why-integer-overflows-are-still-a-thing-1n01 for mitigation details.
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 | 4.8 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | High | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | None | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
NVD: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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