CVE-2020-5260
Description
A flaw was found in git. Credentials can be leaked through the use of a crafted URL that contains a newline, fooling the credential helper to give information for a different host. Highest threat from the vulnerability is to data confidentiality.
Statement
Red Hat Enterprise Linux 6 is not affected by this flaw as the vulnerable version of git, version 1.7.9-rc0 and later, was never packaged for this instance of RHEL.
Mitigation
The most complete workaround is to disable credential helpers altogether:
git config --unset credential.helper
git config --global --unset credential.helper
git config --system --unset credential.helper
An alternative is to avoid malicious URLs:
1. Examine the hostname and username portion of URLs fed to git clone for the presence of encoded newlines (%0a) or evidence of credential-protocol injections (e.g., host=github.com)
2. Avoid using submodules with untrusted repositories (don't use clone --recurse-submodules; use git submodule update only after examining the URLs found in .gitmodules)
3. Avoid tools which may run git clone on untrusted URLs under the hood
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 | 7.5 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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
Red Hat would like to thank the Git project for reporting this issue. Upstream acknowledges Felix Wilhelm (Google project zero) as the original reporter.
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