CVE-2021-43396:Vulnerability in GNU C Library (glibc) iconv() function allowing emission of spurious null characters when processing ISO-2022-JP-3 data.

splash
Back

Description Preview

CVE-2021-43396 affects the GNU C Library (glibc) version 2.34, specifically in the iconvdata/iso-2022-jp-3.c file. The vulnerability allows remote attackers to force the iconv() function to emit a spurious '\0' character when processing crafted ISO-2022-JP-3 data that includes an internal state reset. This can potentially affect data integrity in certain iconv() use cases. However, according to the vendor, this vulnerability requires iconv to be invoked with a NULL inbuf, which would typically require a separate application bug to occur unintentionally, thus limiting the security impact.

Overview

The vulnerability exists in the GNU C Library's implementation of the ISO-2022-JP-3 character encoding conversion. When processing specially crafted data that includes an internal state reset, the iconv() function can be forced to emit an unintended null character ('\0'). This behavior could potentially lead to data integrity issues in applications that rely on the iconv() function for character encoding conversion.

The vulnerability was identified by the TuxCare team and requires specific conditions to be exploited. According to the vendor, the bug can only be triggered when iconv() is invoked with a NULL inbuf parameter, which is considered an unusual usage pattern that would typically require a separate application bug to occur in real-world scenarios.

Remediation

To remediate this vulnerability, system administrators should:

  1. Update the GNU C Library (glibc) to a patched version that includes the fix for this issue.
  2. Apply vendor-specific patches as they become available, such as those included in the Oracle Critical Patch Update from July 2022.
  3. If immediate updating is not possible, review applications that use iconv() for ISO-2022-JP-3 encoding conversion and ensure they do not pass NULL inbuf parameters to the function.
  4. Monitor vendor advisories for updates related to this vulnerability.

The fix for this issue has been committed to the glibc repository (commit hash: ff012870b2c02a62598c04daa1e54632e020fd7d).

References

  1. TuxCare Team Advisory: https://blog.tuxcare.com/vulnerability/vulnerability-in-iconv-identified-by-tuxcare-team-cve-2021-43396
  2. Sourceware Bugzilla Issue: https://sourceware.org/bugzilla/show_bug.cgi?id=28524
  3. Glibc Fix Commit: https://sourceware.org/git/?p=glibc.git;a=commit;h=ff012870b2c02a62598c04daa1e54632e020fd7d
  4. Oracle Critical Patch Update (July 2022): https://www.oracle.com/security-alerts/cpujul2022.html

Industry ExposureMost to least
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.

  1. Manufacturing
    Manufacturing
  2. Health Care & Social Assistance
    Health Care & Social Assistance
  3. Professional, Scientific, & Technical Services
    Professional, Scientific, & Technical Services
  4. Public Administration
    Public Administration
  5. Retail Trade
    Retail Trade
  6. Arts, Entertainment & Recreation
    Arts, Entertainment & Recreation
  7. Finance and Insurance
    Finance and Insurance
  8. Educational Services
    Educational Services
  9. Other Services (except Public Administration)
    Other Services (except Public Administration)
  10. Transportation & Warehousing
    Transportation & Warehousing
  11. Management of Companies & Enterprises
    Management of Companies & Enterprises
  12. Accommodation & Food Services
    Accommodation & Food Services
  13. Administrative, Support, Waste Management & Remediation Services
    Administrative, Support, Waste Management & Remediation Services
  14. Agriculture, Forestry Fishing & Hunting
    Agriculture, Forestry Fishing & Hunting
  15. Construction
    Construction
  16. Information
    Information
  17. Mining
    Mining
  18. Real Estate Rental & Leasing
    Real Estate Rental & Leasing
  19. Utilities
    Utilities
  20. Wholesale Trade
    Wholesale Trade

Focus on What Matters

  1. See Everything.
  2. Identify True Risk.
  3. Proactively Mitigate Threats.

Let's talk!

background