Affected versions: Debian 11 (bullseye)

📖 ~4 min read  •  Source: Debian Security Tracker

Related CVEs: CVE-2015-0234 CVE-2017-7537 CVE-2018-1080 CVE-2019-10146 CVE-2019-10178 CVE-2019-10179 CVE-2019-10180 CVE-2019-10221  +9 more

Upstream summary: Multiple temporary file creation vulnerabilities in pki-core 10.2.0.

Table of contents
  1. Symptom & Impact
  2. Environment & Reproduction
  3. Root Cause Analysis
  4. Quick Triage
  5. Step-by-Step Diagnosis
  6. Solution – Primary Fix
  7. Solution – Alternative Approaches
  8. Verification & Acceptance Criteria
  9. Rollback Plan
  10. Prevention & Hardening
  11. Related Errors & Cross-Refs
  12. References & Further Reading

Symptom & Impact

On Debian 11 hosts running dogtag-pki, the vulnerable code is started by something else – a web or application server, or an on-demand supervisor such as inetd, xinetd or a systemd socket unit – rather than by a service of its own. Patching replaces the files on disk immediately, but a long-running parent that has already loaded them (PHP-FPM workers, an application server, a persistent worker pool) keeps serving the old code until it is recycled. Connection-per-process supervisors pick the fix up on the next connection, so the exposure window differs sharply between the two and is worth confirming rather than assuming. dogtag-pki is started by a hosting server or an on-demand supervisor rather than by a unit of its own, so restart whatever launches it – not dogtag-pki.

Environment & Reproduction

Reproduction targets Debian 11 (bullseye). Confirm release and installed package:

cat /etc/debian_version
lsb_release -a 2>/dev/null || cat /etc/os-release
dpkg -l dogtag-pki | tail -2
apt-cache policy dogtag-pki
dpkg-query -W -f='${Status}\n' dogtag-pki

Exercise the workload that uses dogtag-pki while collecting:

needrestart -b -r l  # (pkg: needrestart) run as root; machine-readable. NEEDRESTART-SVC = units still mapping deleted libs, NEEDRESTART-SESS = login sessions, NEEDRESTART-KSTA = kernel state. -r l never restarts anything
needrestart -v -l -r l  # human-readable, libraries only (-l); names each PID and the obsolete file it still maps
checkrestart -v  # (pkg: debian-goodies) older alternative; add -p to report only deleted files owned by a dpkg package, -m for machine-readable
sudo journalctl -xe --no-pager | tail -200
sudo tail -200 /var/log/apt/history.log
sudo tail -200 /var/log/dpkg.log

Root Cause Analysis

Root cause is tracked at Debian Security Tracker. The Debian Security Team shipped fixes in the corresponding dogtag-pki point release for Debian 11 (suite bullseye-security); running an outdated build leaves the host exposed to the failure modes referenced above. Correlate apt history with the journal:

grep -A2 -B2 dogtag-pki /var/log/apt/history.log
zgrep -A2 -B2 dogtag-pki /var/log/apt/history.log.*.gz 2>/dev/null
cat /proc/sys/kernel/tainted   # non-zero = tainted kernel / out-of-tree modules

Quick Triage

Run these on Debian 11 to capture the current state of dogtag-pki:

dpkg -l dogtag-pki | tail -1                   # installed version
dpkg -V dogtag-pki                              # verify shipped files
sudo apt update && apt list --upgradable 2>/dev/null | grep -i security
systemctl --failed --no-pager
sudo nft list ruleset 2>/dev/null | head -50
sudo aa-status 2>/dev/null | head -20      # AppArmor profiles
dpkg-query -L dogtag-pki 2>/dev/null | grep -E '^/etc/init\.d/[^/]+$'  # legacy SysV init script; its basename is the service name for 'service <name> restart' on non-systemd hosts
systemctl list-unit-files --no-pager --type=service,socket,timer | grep -iF -- 'dogtag-pki'  # fuzzy name match; -F is required because package names contain regex metacharacters ('+' in libstdc++6/g++-13 makes -E fail to match at all)

Step-by-Step Diagnosis

  1. List failed systemd units.

    systemctl --failed --no-pager
  2. Tail the journal for dogtag-pki and the system bus.

    sudo journalctl -xe -f --no-pager
  3. Inspect firewall state (this OS defaults to nftables).

    sudo nft list ruleset
    sudo nft list tables
  4. Verify dogtag-pki file integrity and reinstall if anything is altered.

    sudo dpkg -V dogtag-pki
    sudo debsums -c dogtag-pki 2>/dev/null
    sudo apt install --reinstall -y dogtag-pki
  5. Check AppArmor denials (Debian 11+ default-enabled).

    sudo journalctl -k | grep -i 'apparmor="DENIED"' | tail -30
    sudo aa-status | grep -i dogtag
  6. Correlate findings with /var/log/apt/history.log, /var/log/dpkg.log, and Debian Security Tracker to pin the change that introduced the regression.

Solution – Primary Fix

Apply the corrective apt transaction documented in Debian Security Tracker from the security suite, then reload the affected unit:

sudo apt update
sudo apt -y install --only-upgrade dogtag-pki
sudo systemctl daemon-reload
# Unit name may differ from package name; check first:
systemctl daemon-reload  # only if the upgrade shipped changed unit files
systemctl daemon-reexec  # REQUIRED after a systemd / libsystemd upgrade: re-execs PID 1 against the new library without rebooting (needrestart flags this as 'systemd-manager')
needrestart -r i  # (pkg: needrestart) interactive: prompts per service. The safe default on a production box
needrestart -r a  # non-interactive: restarts EVERY flagged unit. Maintenance window only -- it will bounce databases and web servers without asking
dpkg -l dogtag-pki | tail -1                # confirm new version

For kernel / glibc / systemd / openssl advisories a reboot is required:

sudo apt install -y needrestart
sudo needrestart -r l       # list services that need restart
sudo systemctl reboot       # or: sudo shutdown -r now

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Solution – Alternative Approaches

If the primary upgrade is not viable, pick from these:

  • Pin a known-good version via apt preferences:

    # /etc/apt/preferences.d/dogtag-pki.pref
    Package: dogtag-pki
    Pin: version <good-version>
    Pin-Priority: 1001
  • Mark the package on hold so apt cannot upgrade it:

    sudo apt-mark hold dogtag-pki
    apt-mark showhold | grep dogtag-pki
    # Release the hold later with:
    sudo apt-mark unhold dogtag-pki
  • Downgrade to an older NVR if a regression is suspected:

    apt-cache madison dogtag-pki
    sudo apt install --allow-downgrades -y dogtag-pki=<older-version>
  • Switch firewall backend between iptables-legacy and nftables (Debian 10+):

    sudo update-alternatives --config iptables
    sudo update-alternatives --config ip6tables
    sudo systemctl restart netfilter-persistent 2>/dev/null
  • Take only the security archive update and defer the full point-release upgrade:

    # /etc/apt/sources.list.d/bullseye-security-only.list
    deb http://security.debian.org/debian-security bullseye-security main contrib non-free
    # then:
    sudo apt update && sudo apt -y install --only-upgrade -t bullseye-security dogtag-pki
  • Investigate AppArmor blocking the new binary; switch the profile to complain mode briefly:

    # reproduce, capture denials, then re-enforce:

Verification & Acceptance Criteria

All of these should pass after the fix is applied:

dpkg -l dogtag-pki | tail -1                                  # expected fixed version
apt list --upgradable 2>/dev/null | grep -i security || echo OK
sudo nft list ruleset | head
sudo aa-status 2>/dev/null | head -5

The conditions described in the advisory must no longer be reported for dogtag-pki across two consecutive runs.

Rollback Plan

Capture state before any change:

apt list --installed 2>/dev/null > /root/apt-pre.txt
dpkg --get-selections > /root/dpkg-pre.txt
# LVM snapshot of the root LV (only if root sits on LVM):
sudo lvcreate -L 4G -s -n root_pre_patch /dev/<vg>/<root-lv>

To revert:

sudo apt install --allow-downgrades -y dogtag-pki=<old-version>
sudo systemctl daemon-reload
# If a kernel was rolled back, reboot and select the previous kernel from GRUB:
sudo systemctl reboot
# LVM snapshot merge (offline / on next reboot):
sudo lvconvert --merge /dev/<vg>/root_pre_patch

Prevention & Hardening

Reduce the chance of this recurring on Debian 11:

  • Enable scheduled security updates via unattended-upgrades:

    sudo apt install -y unattended-upgrades apt-listchanges
    sudo dpkg-reconfigure -plow unattended-upgrades
    # /etc/apt/apt.conf.d/50unattended-upgrades:
    Unattended-Upgrade::Origins-Pattern { "origin=Debian,codename=${distro_codename},label=Debian-Security"; };
  • Install needrestart so services restart automatically after library upgrades:

    sudo apt install -y needrestart
    # /etc/needrestart/needrestart.conf -> $nrconf{restart} = 'a';
  • Subscribe to debian-security-announce and watch security-tracker.debian.org.

  • Mirror locally for controlled rollouts:

    sudo apt install -y apt-mirror
    # /etc/apt/mirror.list:
    deb http://deb.debian.org/debian bullseye main contrib non-free
    deb http://security.debian.org/debian-security bullseye-security main contrib non-free
    sudo apt-mirror
  • Monitor file integrity with debsums and AIDE:

    sudo apt install -y debsums aide
    sudo debsums -ca           # report only changed conffile-less files
    sudo aideinit && sudo mv /var/lib/aide/aide.db.new /var/lib/aide/aide.db
    sudo aide --check
  • Apply CIS Debian Linux Benchmark hardening and review auditd rules in /etc/audit/rules.d/.

Issues that commonly surface alongside a dogtag-pki update: apt lock contention, broken dpkg state, systemd ordering cycles, AppArmor denials, and firewall rule drift. Useful triage:

sudo dpkg --configure -a
sudo apt --fix-broken install
systemd-analyze critical-chain
sudo journalctl -k | grep -i apparmor | tail
cat /proc/sys/kernel/tainted

View all debian-11 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Primary reference: Debian Security Tracker. Manual pages useful on Debian 11:

man apt
man apt-get
man apt-mark
man dpkg
man systemctl
man journalctl
man nft
man apparmor
man unattended-upgrades

Other resources: The Debian Administrator’s Handbook, Debian Security FAQ, Debian Security Tracker, and per-package notes in /usr/share/doc/dogtag-pki/ for components implicated in this advisory.