A safety flaw in Travis CI doubtlessly uncovered the secrets and techniques of hundreds of open supply tasks that depend on the hosted steady integration service. Travis CI is a software-testing resolution utilized by over 900,000 open supply tasks and 600,000 customers. A vulnerability within the software made it attainable for safe surroundings variables—signing keys, entry credentials, and API tokens of all public open supply tasks—to be exfiltrated.
Worse, the dev group is upset concerning the poor dealing with of the vulnerability disclosure course of and the temporary “security bulletin” it needed to pressure out of Travis.
Setting variables injected into pull request builds
Travis CI is a well-liked software-testing software resulting from its seamless integration with GitHub and Bitbucket. Because the makers of the software explain:
While you run a construct, Travis CI clones your GitHub repository right into a brand-new digital surroundings and carries out a sequence of duties to construct and check your code. If a number of of these duties fail, the construct is taken into account damaged. If not one of the duties fail, the construct is taken into account handed and Travis CI can deploy your code to an online server or utility host.
However this month, researcher Felix Lange discovered a safety vulnerability that prompted Travis CI to incorporate safe surroundings variables of all public open supply repositories that use Travis CI into pull request builds. Setting variables can embrace delicate secrets and techniques like signing keys, entry credentials, and API tokens. If these variables are uncovered, attackers can abuse the secrets and techniques to acquire lateral motion into the networks of hundreds of organizations.
A easy GitHub search demonstrates that Travis is in widespread use by a lot of tasks:
Tracked as CVE-2021-41077, the bug is current in Travis CI’s activation course of and impacts sure builds created between September 3 and September 10. As part of this activation process, builders are supposed so as to add a “.travis.yml” file to their open supply challenge repository. This file tells Travis CI what to do and should comprise encrypted secrets. However these secrets and techniques will not be meant to be uncovered. In actual fact, Travis CI’s docs have at all times acknowledged, “Encrypted environment variables are not available to pull requests from forks due to the security risk of exposing such information to unknown code.”
Ideally, for a customer-provided “travis.yml” file current in a Git repository, Travis is anticipated to run in a fashion that stops public entry to any secret surroundings variables specified within the YML file. Put merely, when a public challenge is forked (copied), the “.travis.yml” file, together with these secrets and techniques, is included within the fork. That is not presupposed to occur. However this vulnerability prompted these kinds of secrets and techniques to be unexpectedly uncovered to only about anybody forking a public repository and printing recordsdata throughout a construct course of.
Thankfully, the difficulty did not final too lengthy—round eight days, because of Lange and different researchers who notified the corporate of the bug on September 7. However out of warning, all tasks counting on Travis CI are suggested to rotate their secrets and techniques.
Whereas not precisely comparable in nature, the vulnerability has echoes of the Codecov supply chain attack during which menace actors had exfiltrated secrets and techniques and delicate surroundings variables of many Codecov prospects from their CI/CD environments, resulting in additional information leaks at distinguished corporations.
“According to a received report, a public repository forked from another one could file a pull request (standard functionality, e.g., in GitHub, BitBucket, Assembla) and while doing it obtain unauthorized access to secrets from the original public repository with a condition of printing some of the flies during the build process,” defined Montana Mendy of Travis CI in a security bulletin. “In this scenario, secrets are still encrypted in the Travis CI database.”
Mendy says the difficulty solely applies to public repositories and to not personal repositories, as repository homeowners of the latter have full management over who can fork their repositories.
Neighborhood livid over flimsy “security bulletin”
The presence and comparatively fast patching of the flaw apart, Travis CI’s concise safety bulletin and total dealing with of the coordinated disclosure course of has infuriated the developer group.
In a protracted Twitter thread, Ethereum cryptocurrency challenge lead Péter Szilágyi particulars the arduous course of that his firm endured because it waited for Travis CI to take motion and launch a quick safety bulletin on an obscure webpage.
Between the three Sept and 10 Sept, safe env vars of *all* public @travisci repositories have been injected into PR builds. Signing keys, entry creds, API tokens.
— Péter Szilágyi (karalabe.eth) (@peter_szilagyi) September 14, 2021
“After 3 days of pressure from multiple projects, [Travis CI] silently patched the issue on the 10th. No analysis, no security report, no post mortem, not warning any of their users that their secrets might have been stolen,” tweeted Szilágyi.
After Szilágyi and Lange requested GitHub to ban Travis CI over its poor safety posture and vulnerability disclosure processes, an advisory confirmed up. “Finally, after multiple ultimatums from multiple projects, [they] posted this lame-ass post hidden deep where nobody will read it… Not even a single ‘thank you.’ [No] acknowledgment of responsible disclosure. Not even admitting the gravity of it all,” mentioned Szilágyi, whereas referring to the safety bulletin—and particularly its abridged version, which included barely any particulars.
Szilágyi was joined by a number of members of the group in criticizing the bulletin. Boston-based net developer Jake Jarvis called the disclosure an “insanely embarrassing ‘security bulletin.'”
However Travis CI thinks rotating secrets and techniques is one thing builders must be doing anyway. “Travis CI implemented a series of security patches starting on Sept 3rd that resolves this issue,” concluded Mendy on behalf of the Travis CI crew. “As a reminder, cycling your secrets is something that all users should do on a regular basis. If you are unsure how to do this, please contact Support.”
Ars has reached out to each Travis CI and Szilágyi for additional remark, and we’re awaiting their responses.
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