T03 · Remote Payload Retrieval and Execution
- Location
SKILL.md:116- Finding
Unverified Remote Installer Is Downloaded and Executed by Bash
- Content
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Vulnerability Details
File Location:
SKILL.md, lines 116–121
Vulnerability Type: Remote payload retrieval and execution
Risk Level: HighVulnerable Code
bash # One-click installation /bin/bash -c "$(curl -fsSL https://aliyuncli.alicdn.com/install.sh)"Technical Analysis
The documented installation command retrieves a mutable shell script from an external URL and immediately executes its contents with Bash. It does not pin a release, verify a cryptographic signature or checksum, or provide an opportunity to inspect the downloaded script before execution.
Although HTTPS protects the connection under normal conditions, it does not establish that the remotely hosted script is immutable or independently verify its contents. Compromise of the hosting infrastructure, publication pipeline, domain, or trusted TLS path could therefore turn this installation step into arbitrary code execution. The payload can also change after the skill package has been audited.
Attack Path
- An attacker compromises or gains control over the remote installer, its publication infrastructure, or a trusted delivery path.
- The attacker modifies
install.shto include malicious shell commands. - A user or agent follows the prerequisite instructions in
SKILL.md. curldownloads the modified content into command substitution./bin/bash -cexecutes the content immediately with the privileges of the invoking user.- The payload can access files, environment variables, and cloud CLI credentials available to that account, and may perform further actions allowed by the account.
Impact Assessment
Successful exploitation provides arbitrary command execution with the invoking user's privileges. Potential consequences include theft or modification of Alibaba Cloud credentials, unauthorized cloud API operations within those credentials' permissions, alteration of local files, installation of persistence mechanisms, and execution of addition ...[truncated 272 chars]
- Remediation
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Remediation Suggestions
- Remove the direct
curl | bash-equivalent installation workflow. - Pin the Alibaba Cloud CLI to a specific reviewed version rather than retrieving a mutable installer.
- Download the release artifact as a separate step from a documented official release location.
- Verify the artifact using a vendor-published cryptographic signature. If signatures are unavailable, verify a SHA-256 checksum obtained through an independently authenticated channel.
- Abort installation if verification fails.
- Extract or execute the verified artifact only after validation, using the minimum privileges required.
- Document package-manager installation as an alternative where the package repository supplies signature verification and version pinning.
- Periodically review and deliberately update the pinned version and expected signature or checksum.
A hardened workflow should follow this sequence:
bash # Illustrative workflow; replace placeholders with vendor-published values. VERSION="<PINNED_VERSION>" EXPECTED_SHA256="<VENDOR_PUBLISHED_SHA256>" curl --fail --show-error --location \ --output "aliyun-cli-${VERSION}.tar.gz" \ "<OFFICIAL_VERSIONED_RELEASE_URL>" printf '%s %s\n' "$EXPECTED_SHA256" "aliyun-cli-${VERSION}.tar.gz" \ | sha256sum --check --strict # Continue installation only if verification succeeds.- Remove the direct