CVE Vendor Advisory AttackerKB IVM Content Patching Urgency Last Update
CVE-2021-22205 GitLab Advisory AttackerKB Evaluating ASAP November 1, 2021

On April 14, 2021, GitLab published a security release to address CVE-2021-22205, a critical remote code execution vulnerability in the service’s web interface. At the time, GitLab described the issue as an authenticated vulnerability that was the result of passing user-provided images to the service’s embedded version of ExifTool. A remote attacker could execute arbitrary commands as the git user due to ExifTool’s mishandling of DjVu files, an issue that was later assigned CVE-2021-22204.

CVE-2021-22205 was initially assigned a CVSSv3 score of 9.9. However, on September 21, 2021 GitLab revised the CVSSv3 score to 10.0. The increase in score was the result of changing the vulnerability from an authenticated issue to an unauthenticated issue. Despite the tiny move in CVSS score, a change from authenticated to unauthenticated has big implications for defenders. Rapid7’s vulnerability research team has a full root cause analysis of CVE-2021-22205 in AttackerKB.

There are multiple recently published public exploits for this vulnerability, and it reportedly has been exploited in the wild since June or July of 2021. We expect exploitation to increase as details of the unauthenticated nature of this vulnerability become more widely understood.

According to GitLab’s April 2021 advisory, CVE-2021-22205 affects all versions of both GitLab Enterprise Edition (EE) and GitLab Community Edition (CE) starting from 11.9. The vulnerability was patched in the following versions:

  • 13.10.3
  • 13.9.6
  • 13.8.8

Versions in the wild

At the time of writing (October 31, 2021), patches have been available for GitLab for more than six months. However, analysis of internet-facing GitLab instances suggests that a large number are still vulnerable.

We can see just short of 60,000 internet-facing GitLab installations. Unfortunately, GitLab’s web interface does not have an easy-to-extract version string. But by using the appearance of application_utilities about a year ago and then the migration of application_utilities into loading hints header, we can break the internet-facing GitLab installs into three categories: unpatched, maybe patched, and patched.

Of the 60,000 this is what we found:

  • 21% of installs are fully patched against this issue.
  • 50% of installs are not patched against this issue.
  • 29% of installs may or may not be vulnerable.

Mitigation guidance

Rapid7’s emergent threat response team has a full technical analysis of CVE-2021-22205 in AttackerKB, along with several ways for GitLab customers to determine whether they may be running vulnerable versions.

GitLab users should upgrade to the latest version of GitLab as soon as possible. In addition, ideally, GitLab should not be an internet facing service. If you need to access your GitLab from the internet, consider placing it behind a VPN.

Rapid7 customers

Our researchers are currently evaluating the feasibility of adding a vulnerability check for CVE-2021-22205.

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