CVE-2024-52587

EUVD-2024-3251 · Published Nov 18, 2024

Harden-Runner has a command injection weaknesses in setup.ts and arc-runner.ts

Summary

Versions of step-security/harden-runner prior to v2.10.2 contain multiple command injection weaknesses via environment variables that could potentially be exploited under specific conditions. However, due to the current execution order of pre-steps in GitHub Actions and the placement of harden-runner as the first step in a job, the likelihood of exploitation is low as the Harden-Runner action reads the environment variable during the pre-step stage. There are no known exploits at this time.

Details

setup.ts:169 1 performs execSync with a command that gets
invoked after interpretation by the shell. This command includes an
interpolated process.env.USER variable, which an attacker could
modify (without actually creating a new user) to inject arbitrary
shell expressions into this execSync. This may or may not be likely
in practice, but I believe the hygienic way to perform the underlying
operation is to use execFileSync or similar and bypass the
underlying shell evaluation.
setup.ts:229 2 has a nearly identical execSync to (1) above,
but with $USER for shell-level interpolation rather than string
interpolation. However, this is still injectable and would be best
replaced by an execFileSync, per above.
arc-runner:40-44 3 has an execSync with multiple string
interpolations. Most of these do not appear immediately injectible
(since they appear to come from presumed trusted API responses), but
the expansion of getRunnerTempDir() may be injectable due to its
dependence on potentially attacker-controllable environment variables
(e.g. RUNNER_TEMP). The underlying operation appears to be a trivial
file copy, so this entire subprocess should in theory be replaceable
with ordinary NodeJS fs API calls instead.
arc-runner:53 4 demonstrates the same weakness, and has the same
resolution as (3).
arc-runner:57 demonstrates the same weakness as (3) and (4), and
has the same resolution.
arc-runner:61 demonstrates the same weakness as (3), (4), and (5),
and has the same resolution.

Technologies

Step-Security Harden-Runner

Weaknesses

CWE-78

CVSS scores

v3.18.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Initial Access

T1190Exploit Public-Facing Application

References

Potentially impacted assets

See if this affects your attack surface

Latest trending attack

Criticalyesterday

Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)

This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it. Why a second control CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution. Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library. The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support. What this control checks Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service. How to read the result Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside. This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification. Affected and fixed versions Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution. Recommendations Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library. Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli. Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.