append-only-veccrates.io
append-only-vec is a confirmed malicious crates.io package (MAL-2026-14333) that opens a backdoor for remote access (malicious version 0.1.9). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in append_only_vec (crates.io)
What this malware does
append-only-vec 0.1.9 was published to crates.io from the same maintainer account (droundy) as the trojanized arrayref and internment releases, which appears to be compromised. The release adds a dependency on an attacker-controlled crate whose build script downloads and executes an architecture-specific remote binary at build time from https://23.254.165.112:9089/, passing 23.254.165.112:443 as a command-and-control address. Part of a coordinated crates.io campaign on 2026-08-20. The malicious release has been removed from crates.io; earlier append-only-vec releases are unaffected.
Malicious versions
Detection & response playbook
Backdoor / remote accessFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for append-only-vec (version 0.1.9). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging append-only-vec across your stack and pipelines.
If you installed it — respond
append-only-vec establishes remote access, so treat any host that installed it as fully compromised. Isolate the machine, remove the package, rotate all credentials it could reach, and rebuild from a trusted image rather than cleaning in place — a backdoor may have planted additional persistence.
Did it already run?
If append-only-vec was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks append-only-vec before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
References
Credits
- SafeDep · finder
- jhobern · reporter
Detect & block this
O3 blocks append-only-vec-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the C2 callback and severs the channel.