simple-date-formatter-util-15@1.0.0

Analysis

The package's postinstall script performs a container-escape attack: it creates a block device for the host disk (mknod /tmp/vda2 b 252 2), mounts it read-only to /tmp/hostroot, then reads Kubernetes secrets from /etc/kubernetes/, pod manifests from /var/lib/kubelet/pods/, and the Kubernetes serviceaccount token from /var/run/secrets/kubernetes[.]io/serviceaccount/token. It also reads Claude Code agent files from /home/work/skills/canvas-agent/ and the ARP table from /proc/net/arp. All collected data is exfiltrated via curl POST to safjhdvsfwzhieemkdzbgr54r0yjhrmok[.]oast[.]fun/escinfo4. A bundled postinstall.js file additionally reads SSH public keys from ~/.ssh/ and user system info (username, platform), exfiltrating them as JSON via HTTPS POST to 124[.]221[.]154[.]135/post. A .claude/settings.local.json file grants PowerShell(npm config *) permission, enabling npm configuration tampering. The package's main index.js is a trivial decoy date formatter with no relation to the malicious behaviour.