NetBSD 9.4 — ethereal — vulnerability — patch and remediation guide

📖 ~4 min read  •  Source: pkgsrc audit-packages entry

Related CVEs: CVE-2006-3627

Upstream summary: pkgsrc audit-packages flagged ethereal<=0.8.13 for vulnerability class 'remote-root-shell'. Reference: http://www.securityfocus.com/frames/?content=/templates/archive.pike%3Ffromthread%3D1%26end%3D2000-11-25%26mid%3D145761%26start%3D2000-11-19%26list%3D1%26threads%3D0%26

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 NetBSD 9.4 hosts that have ethereal installed from pkgsrc, operators report behaviour consistent with the pkgsrc audit-packages entry entry: pkg_admin audit flags the installed package as vulnerable, services launched from /etc/rc.d that link against ethereal may misbehave or refuse to start after an upgrade, and — for security-rated advisories — the host is exposed to the vulnerability set above. Impact ranges from a single service restart cycle to a full availability incident when ethereal sits on the serving path of an NetBSD server.

Environment & Reproduction

Reproduction targets NetBSD 9.4. Confirm release, kernel, and installed package state:

uname -a
cat /etc/release
sysctl kern.version
sysctl kern.osrelease
pkg_info -e ethereal && pkg_info ethereal | head -20
pkgin list | wc -l

Trigger the workflow that exposes ethereal — vulnerability — patch and remediation guide while collecting:

tail -200 /var/log/messages
tail -200 /var/log/authlog
dmesg | tail -200
# pkgsrc transaction log (location varies; check both):
tail -200 /var/db/pkgin/pkg_install-err.log 2>/dev/null
tail -200 /var/log/pkgsrc.log 2>/dev/null

Root Cause Analysis

Root cause is tracked at pkgsrc audit-packages entry. NetBSD pkgsrc-security maintains the pkg-vulnerabilities feed consumed by pkg_admin audit; hosts running a pre-fix build of ethereal remain exposed. Correlate audit output with system logs and kernel state to identify the change that introduced the failure mode:

sudo pkg_admin fetch-pkg-vulnerabilities   # refresh the audit feed first
sudo pkg_admin audit-pkg ethereal             # per-package audit
sudo pkg_admin audit                       # full-system audit
tail -500 /var/log/messages
sysctl kern.lastpid kern.osreldate
# Verify the running base kernel matches the on-disk image:
cksum -a sha256 /netbsd

Quick Triage

Run these checks on NetBSD 9.4 to confirm the failure mode and the current state of ethereal:

pkgin search ^ethereal$                       # confirm pkgin can see it
pkgin show-deps ethereal                      # forward dependencies
pkgin show-rev-deps ethereal                  # reverse dependencies
sudo pkg_admin audit-pkg ethereal             # audit just this package
tail -100 /var/log/messages
tail -100 /var/log/authlog
dmesg | tail -100
# If ethereal ships an rc.d script (script name may differ, e.g.
# bind→named, php→php_fpm, apache→apache), check it:
grep -l ethereal /etc/rc.d/* 2>/dev/null
service -e 2>/dev/null | grep -i ethereal
# Firewall posture (npf is default in NetBSD 10; ipf still available):
npfctl show 2>/dev/null || ipfstat -hin 2>/dev/null

Step-by-Step Diagnosis

1. Refresh the pkgsrc audit feed and run a full system audit.

   sudo pkg_admin fetch-pkg-vulnerabilities
   sudo pkg_admin audit

2. Tail live logs while reproducing the issue.

   tail -F /var/log/messages
   tail -F /var/log/authlog
   dmesg | tail -200

3. Inspect firewall rules — NetBSD 10 defaults to npf, older deployments may still run ipf.

   npfctl rule "block-in" list 2>/dev/null
   npfctl show 2>/dev/null
   ipfstat -hin 2>/dev/null
   ipfstat -nio 2>/dev/null

4. Confirm enabled services in /etc/rc.conf and current daemon state.

   grep -E '=YES' /etc/rc.conf
   service -e 2>/dev/null | grep -i ethereal
   sudo service <rc-script-name> status

5. Verify the on-disk integrity of the package files for ethereal.

   pkg_admin check ethereal
   pkg_info -L ethereal | xargs -I{} cksum -a sha256 {} 2>/dev/null | head

6. Correlate findings with the NetBSD source CVS log and pkgsrc audit-packages entry to pin the change that introduced ethereal — vulnerability — patch and remediation guide.

Solution – Primary Fix

Refresh the pkgsrc package index and upgrade ethereal (and its dependants) through pkgsrc audit-packages entry:

sudo pkgin update
sudo pkgin upgrade ethereal            # single package
sudo pkgin full-upgrade             # whole-system pkgsrc upgrade
sudo pkg_admin fetch-pkg-vulnerabilities
sudo pkg_admin audit-pkg ethereal      # confirm no remaining audit entry
# If ethereal ships an rc.d service, restart it (the rc-script name may differ from pkg name):
# sudo service <rc-script-name> restart

For administrators who build from a local pkgsrc tree:

# Refresh the tree (CVS) or pull a fresh tarball:
cd /usr/pkgsrc && sudo cvs -q update -dP
cd /usr/pkgsrc/<category>/ethereal && sudo make replace clean
# Or rebuild + binary package output:
cd /usr/pkgsrc/<category>/ethereal && sudo make package-install

For base-system fixes, NetBSD does not ship binary syspatches like OpenBSD. Rebuild from source (CVS or release tarball) or move to a newer build:

# Option A: in-place upgrade via the sysupgrade pkgsrc tool:
sudo pkgin install sysupgrade
sudo sysupgrade auto https://nycdn.NetBSD.org/pub/NetBSD-daily/netbsd-10/latest/amd64/
# Option B: rebuild from the source tree:
cd /usr/src && sudo ./build.sh -O /var/obj -T /var/tools -U tools
cd /usr/src && sudo ./build.sh -O /var/obj -T /var/tools -U distribution
cd /usr/src && sudo ./build.sh -O /var/obj -T /var/tools -U install=/
# Option C: fetch a HEAD/release tarball and extract base.tgz over /:
cd /var/tmp && ftp https://nycdn.NetBSD.org/pub/NetBSD-daily/netbsd-10/latest/amd64/binary/sets/base.tgz
cd / && sudo tar xzpf /var/tmp/base.tgz

Reboot only if the upgrade replaced the kernel (/netbsd) or shared libraries used by long-running daemons.

Solution – Alternative Approaches

If the primary fix is not viable, choose from these alternatives:

• Pin the package on its current version while staging a coordinated rollout. pkgsrc has no first-class “lock” so document and reinstall from a saved binary:

  pkg_info -X ethereal > /root/ethereal.pin.txt
  # Save the current .tgz from /usr/pkgsrc/packages/All/ethereal-<ver>.tgz
  # Refuse pkgin upgrades for this package by removing it from the upgrade plan:
  sudo pkgin -y avoid ethereal 2>/dev/null || true

• Roll ethereal back to a known-good binary package:

  # 1. List versions available from the configured pkgin repo:
  pkgin search ^ethereal$
  # 2. Force-install a specific .tgz from a saved build:
  sudo pkg_add -f /usr/pkgsrc/packages/All/ethereal-<older-version>.tgz
  # 3. Or point pkgin at the previous quarterly branch via /usr/pkg/etc/pkgin/repositories.conf

• Switch the pkgin repository between branches by editing /usr/pkg/etc/pkgin/repositories.conf:

  # /usr/pkg/etc/pkgin/repositories.conf
  https://cdn.NetBSD.org/pub/pkgsrc/packages/NetBSD/$arch/$osrelease/All
  # Then:
  sudo pkgin update
  sudo pkgin upgrade ethereal

• Build from source against a different pkgsrc branch (quarterly vs. HEAD):

  cd /usr && sudo cvs -d :pserver:[email protected]:/cvsroot checkout -P pkgsrc
  cd /usr/pkgsrc/<category>/ethereal && sudo make replace clean clean-depends

• Sandbox the affected service with stricter firewall rules until a fix is verified — npf.conf example:

  # /etc/npf.conf
  block in on $ext_if proto tcp to port ethereal_port
  # Reload the ruleset:
  sudo npfctl reload
  sudo npfctl show

• Replace the service with a vendored static build for the interval between exposure detection and full rollout.

Verification & Acceptance Criteria

All of these should pass after the fix:

pkg_info ethereal                           # shows the expected fixed version
sudo pkg_admin audit-pkg ethereal           # no audit hit for this package
sudo pkg_admin audit                     # no audit hits anywhere
tail -50 /var/log/messages              # no new errors after upgrade
tail -50 /var/log/authlog               # no auth anomalies
# If ethereal ships an rc.d service, confirm it is running:
# sudo service <rc-script-name> status
# Verify base kernel integrity if the upgrade touched /netbsd:
cksum -a sha256 /netbsd

The original reproduction for ethereal — vulnerability — patch and remediation guide must not trigger across two consecutive runs.

Rollback Plan

Capture state before any change:

pkg_info -X > /root/pkg-pre.txt
cp -a /etc/rc.conf /etc/rc.conf.pre-patch
# Snapshot the root filesystem if you are on ZFS:
sudo zfs snapshot rpool/ROOT/netbsd@pre-ethereal-patch 2>/dev/null || true

To revert if the upgrade is bad:

# Reinstall the previously saved binary package:
sudo pkg_add -f /usr/pkgsrc/packages/All/ethereal-<previous-version>.tgz
# Or roll back via pkgin if a previous version is still in the repo:
sudo pkgin install ethereal-<previous-version>
# Restore rc.conf if it was edited:
sudo cp /etc/rc.conf.pre-patch /etc/rc.conf
# Rollback ZFS snapshot (only if you took one above):
sudo zfs rollback rpool/ROOT/netbsd@pre-ethereal-patch 2>/dev/null || true

For a base-system / kernel regression, boot the previous kernel from the loader prompt (press 5 at the boot menu, then boot netbsd.old).

Prevention & Hardening

Reduce the chance of this recurring on NetBSD 9.4 hosts running ethereal:

• Schedule a daily pkgsrc audit via cron:

  # /etc/daily.local
  pkg_admin fetch-pkg-vulnerabilities
  pkg_admin audit | mail -E -s 'pkgsrc audit' root

• Subscribe to netbsd-announce and pkgsrc-security at mail-index.NetBSD.org and watch the NetBSD Security Advisories index.

• Mirror pkgsrc binary packages locally so production hosts pull from a vetted feed:

  # Bulk-build a private pkgsrc repo (one-time):
  cd /usr/pkgsrc/pkgtools/pbulk && sudo make install clean
  sudo pbulk-build -c /usr/pbulk/etc/pbulk.conf
  # Then publish /usr/pbulk/packages/ behind nginx or rsync.

• Keep sysupgrade installed and dry-run it before scheduled windows:

  sudo pkgin install sysupgrade
  sudo sysupgrade -n auto https://nycdn.NetBSD.org/pub/NetBSD-daily/netbsd-10/latest/amd64/

• Harden the firewall with npf default-deny and reload after edits:

  # /etc/npf.conf
  $ext_if = "wm0"
  group default {
    block all
    pass in final on $ext_if proto tcp to port { ssh }
    pass out final all
  }

  sudo npfctl reload
  sudo npfctl start

• Monitor file integrity with the NetBSD-shipped veriexec subsystem or with mtree:

  # mtree baseline of critical config dirs:
  sudo mtree -c -K sha256digest -p /etc       > /var/db/etc.mtree
  sudo mtree -c -K sha256digest -p /usr/pkg/etc > /var/db/usr-pkg-etc.mtree
  # Verify later:
  sudo mtree -p /etc < /var/db/etc.mtree
  # veriexec (kernel-enforced):
  sudo veriexecgen -o /etc/signatures
  sudo veriexecctl load /etc/signatures

• Verify NetBSD signed sets when applying base-system updates — the project publishes detached signatures alongside base.tgz on nycdn.NetBSD.org:

  # Fetch set + signature, then verify before extracting:
  ftp https://nycdn.NetBSD.org/pub/NetBSD-daily/netbsd-10/latest/amd64/binary/sets/base.tgz
  ftp https://nycdn.NetBSD.org/pub/NetBSD-daily/netbsd-10/latest/amd64/binary/sets/SHA512
  grep base.tgz SHA512 | cksum -a sha512 -c -

Related Errors & Cross-Refs

Issues that commonly surface alongside ethereal — vulnerability — patch and remediation guide: mismatched kern.osrelease after a partial userland upgrade, stale shared-library references after a pkgsrc replace, drifted npf rules, and out-of-date pkg-vulnerabilities feeds. Useful triage:

uname -a
sysctl kern.osrelease kern.osreldate
sudo pkg_admin audit
sudo npfctl show

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References & Further Reading

Primary reference: pkgsrc audit-packages entry. Useful manual pages on NetBSD 9.4:

man pkgin
man pkg_admin
man pkg_info
man rc.conf
man rc.d
man service
man npfctl
man npf.conf
man ipf
man sysupgrade
man veriexec

Other resources: the NetBSD Guide, the NetBSD Security Advisories index, the pkgsrc Guide, and the per-package DESCR + MESSAGE files under /usr/pkgsrc/<category>/ethereal/ for notes implicated in ethereal — vulnerability — patch and remediation guide.

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