feat(ssh,telnet): add non-root user account for privesc + enum lure

Real Linux deployments (especially Ubuntu cloud images) ship a non-
root admin user; honeypots that only accept root logins are a tell.
Add a second account on both SSH and Telnet decoys, configurable
via service_cfg keys `user` / `user_password`, defaulting to
`ubuntu` / `admin` so the lure is live on every fresh deploy.

* `decnet/services/{ssh,telnet}.py` — two new ServiceConfigFields
  (`user` string, `user_password` secret) and matching env vars
  (`SSH_USER` / `SSH_USER_PASSWORD`, mirror for telnet) propagated
  via the compose fragment.
* `decnet/templates/ssh/entrypoint.sh` — runtime `useradd -m -s
  /usr/libexec/login-session -G sudo "$SSH_USER"` so the new user
  inherits the same sessrec pty-recording shell as root and lands
  in the sudo group. Privesc attempts (`sudo`) flow through the
  existing sudo-log capture; network-enum from the user's shell
  rides the recorded transcript.
* `decnet/templates/telnet/entrypoint.sh` — same useradd pattern
  (no sudo group — busybox+login telnet image has no sudo
  package; privesc rides `su -` which itself flows through the
  existing PAM auth-helper at /etc/pam.d/login).
* New tests for default + custom user / password + independence
  from root password. Updated the schema-keys assertion to match
  the four-field shape.

The new account is ALSO the natural home for the body-aware
predicates that were previously gated on root-only sessions —
attackers who land on `ubuntu@host` and run network-recon /
privesc commands now generate the same structured TTP-rule
events as root sessions did, captured via the same auth-helper
+ sessrec + sudo-log pipes.
This commit is contained in:
2026-05-02 19:48:03 -04:00
parent c675bd26cf
commit 3e9c4c29b9
6 changed files with 167 additions and 9 deletions

View File

@@ -17,8 +17,11 @@ class SSHService(BaseService):
RFC 5424 via the rsyslog bridge baked into the image.
service_cfg keys:
password Root password (default: "admin")
hostname Override container hostname
password Root password (default: "admin")
user Non-root user name (default: "ubuntu") for
realistic "ssh user@host" lures + privesc capture
user_password Non-root user's password (default: "admin")
hostname Override container hostname
"""
name = "ssh"
@@ -34,6 +37,33 @@ class SSHService(BaseService):
secret=True,
help="Plaintext root password for the in-container sshd.",
),
ServiceConfigField(
key="user",
label="Non-root user",
type="string",
default="ubuntu",
help=(
"Username for the second account on the decoy. Real Linux "
"boxes (especially Ubuntu cloud images) ship a non-root "
"admin user — having one makes the decoy more lifelike, "
"captures attackers who try `ssh user@host` for network "
"enumeration, and surfaces sudo/privesc behaviour the root-"
"only path misses."
),
),
ServiceConfigField(
key="user_password",
label="Non-root user password",
type="password",
default="admin",
secret=True,
help=(
"Password for the non-root user. Captured at PAM auth time "
"via the same auth-helper that handles root logins. The "
"user is in the `sudo` group; subsequent privesc attempts "
"fan out through the existing sudo-log capture."
),
),
ServiceConfigField(
key="hostname",
label="Container hostname",
@@ -55,6 +85,13 @@ class SSHService(BaseService):
cfg = service_cfg or {}
env: dict = {
"SSH_ROOT_PASSWORD": cfg.get("password", "admin"),
# Non-root user account — created at runtime by the entrypoint
# iff SSH_USER is non-empty. Defaults to "ubuntu"/"admin" so
# `ssh ubuntu@<decky>` works out of the box (the conventional
# cloud-init account on Ubuntu cloud images, very low-friction
# for attackers running ssh enumeration scripts).
"SSH_USER": cfg.get("user", "ubuntu"),
"SSH_USER_PASSWORD": cfg.get("user_password", "admin"),
# NODE_NAME is the authoritative decky identifier for log
# attribution — matches the host path used for the artifacts
# bind mount below. The container hostname (optionally overridden

View File

@@ -16,8 +16,11 @@ class TelnetService(BaseService):
are logged as RFC 5424 via the same rsyslog bridge used by the SSH service.
service_cfg keys:
password Root password (default: "admin")
hostname Override container hostname
password Root password (default: "admin")
user Non-root user name (default: "ubuntu") for
realistic "telnet user@host" lures + privesc capture
user_password Non-root user's password (default: "admin")
hostname Override container hostname
"""
name = "telnet"
@@ -33,6 +36,33 @@ class TelnetService(BaseService):
secret=True,
help="Plaintext root password for the in-container telnetd.",
),
ServiceConfigField(
key="user",
label="Non-root user",
type="string",
default="ubuntu",
help=(
"Username for the second account on the decoy. The telnet "
"image is busybox + real /bin/login (PAM-aware), so a "
"non-root user widens the attack surface — captures "
"enumeration scripts that only try common usernames "
"(`telnet ubuntu@host`) and post-login `su -` privesc "
"attempts via the existing PAM auth-helper."
),
),
ServiceConfigField(
key="user_password",
label="Non-root user password",
type="password",
default="admin",
secret=True,
help=(
"Password for the non-root user. Captured at PAM auth "
"time via the same auth-helper that handles root logins. "
"Telnet has no sudo (busybox+login image); privesc rides "
"`su -` which itself flows through PAM."
),
),
ServiceConfigField(
key="hostname",
label="Container hostname",
@@ -54,6 +84,13 @@ class TelnetService(BaseService):
cfg = service_cfg or {}
env: dict = {
"TELNET_ROOT_PASSWORD": cfg.get("password", "admin"),
# Non-root user account — created at runtime by the
# entrypoint iff TELNET_USER is non-empty. Defaults to
# "ubuntu"/"admin" to mirror the SSH service shape and
# match the Ubuntu-flavoured motd already baked into the
# telnet image.
"TELNET_USER": cfg.get("user", "ubuntu"),
"TELNET_USER_PASSWORD": cfg.get("user_password", "admin"),
# NODE_NAME is the authoritative decky identifier for log
# attribution — matches the host path used for the artifacts
# bind mount below.