⚠ Reference material — not professional advice. Test in staging, back up first, verify against your specific version. Use your own judgment for your environment.
● High · CVSS 8.8 ⚠ ACTIVELY EXPLOITED — CISA KEV

How to Fix CVE-2017-6327: Code Execution in Messaging Gateway

Other vulnerabilities in the same area that are worth patching alongside this one:

*By Sai Kiran Pandrala*

⚡ At a glance
SeverityCVSS 8.8, High
Actively exploited?Yes, listed in CISA KEV (added 2021-11-03)
AffectedSymantec Corporation Messaging Gateway (All versions prior to version 10.6.3-267)
Fixed inSee vendor advisory
Type (CWE)Code Execution
⚠️ Patch immediately. CVE-2017-6327 is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03). Federal agencies had until 2022-05-03 to remediate.

What is CVE-2017-6327?

The Symantec Messaging Gateway before 10.6.3-267 can encounter an issue of remote code execution, which describes a situation whereby an individual may obtain the ability to execute commands remotely on a target machine or in a target process. In this type of occurrence, after gaining access to the system, the attacker may attempt to elevate their privileges.

In practical terms, a successful attacker gets remote code execution on the affected system. CISA has confirmed exploitation in the wild, so this is not a theoretical risk.

Am I affected?

You're affected if you run Symantec Corporation Messaging Gateway at any version in the Affected row above. Use these probes to find your installed build:


# Confirm the installed version via your package manager
dpkg -l | grep -i messaging   # Debian/Ubuntu
rpm -qa | grep -i messaging   # RHEL/CentOS/Rocky

How to fix CVE-2017-6327

The primary fix is to upgrade to the patched build listed in the Fixed in row above (See vendor advisory). Pick the platform that matches your install and run the commands below.

Citrix ADC / NetScaler / Gateway (CLI)


# Vendor advisory: http://seclists.org/fulldisclosure/2017/Aug/28
# Confirm version
show version
# Save current config
save config
# Upload the patched build (build-<patched-version>.tgz) to /var/tmp/ then install:
shell
cd /var/tmp && tar -xzf build-<patched-version>.tgz && cd build-<patched-version> && ./installns
# Reboot when the installer prompts

PowerShell script (Windows) - detect, back up, upgrade, verify, log


# Vendor advisory: http://seclists.org/fulldisclosure/2017/Aug/28
# Run as Administrator
$ErrorActionPreference = 'Stop'
$log = "$env:ProgramData\MessagingGateway-Patch-CVE-2017-6327.log"
function Write-Log($msg) { "$(Get-Date -Format s)  $msg" | Tee-Object -FilePath $log -Append }

Write-Log "Starting CVE-2017-6327 remediation for Symantec Corporation Messaging Gateway"

# 1. Detect: replace the path/version probe with one valid for your install
$installed = (Get-WmiObject -Class Win32_Product |
    Where-Object { $_.Name -like '*Messaging*' } |
    Select-Object -First 1 -ExpandProperty Version)
Write-Log "Detected version: $installed"

if (-not $installed) {
    Write-Log "Product not installed on this host; nothing to do."
    return
}
if ([version]$installed -ge [version]'<patched-version>') {
    Write-Log "Already at fixed version $installed; no action needed."
    return
}

# 2. Backup configuration to a timestamped folder
$backup = "$env:ProgramData\MessagingGateway-Backup-$(Get-Date -Format yyyyMMdd-HHmm)"
New-Item -ItemType Directory -Path $backup -Force | Out-Null
# Adjust the source path to match your install
$src = "$env:ProgramFiles\Symantec Corporation\Messaging Gateway"
if (Test-Path $src) { Copy-Item -Path $src -Destination $backup -Recurse -Force }
Write-Log "Backed up config to $backup"

# 3. Apply the patched installer (place the verified file on a share or staging path)
$installer = "$env:TEMP\MessagingGateway-<patched-version>.msi"
if (-not (Test-Path $installer)) {
    throw "Patched installer not found at $installer. Stage it from your software repo first."
}
Start-Process msiexec.exe -ArgumentList "/i `"$installer`" /qn /norestart" -Wait
Write-Log "Installer finished"

# 4. Verify
$verify = (Get-WmiObject -Class Win32_Product |
    Where-Object { $_.Name -like '*Messaging*' } |
    Select-Object -First 1 -ExpandProperty Version)
if ([version]$verify -ge [version]'<patched-version>') {
    Write-Log "SUCCESS: now at $verify (>= <patched-version>)"
} else {
    Write-Log "FAILURE: still at $verify after install"
    exit 1
}

Bash script (Linux) - detect, back up, upgrade, verify, log


# Vendor advisory: http://seclists.org/fulldisclosure/2017/Aug/28
#!/usr/bin/env bash
set -euo pipefail
LOG=/var/log/messaging-gateway-patch-cve-2017-6327.log
log()  { echo "$(date -Iseconds)  $*" | tee -a "$LOG"; }

log "Starting CVE-2017-6327 remediation for Symantec Corporation Messaging Gateway"

# 1. Detect installed version (works for deb and rpm packages)
if command -v dpkg >/dev/null && dpkg -s messaging-gateway >/dev/null 2>&1; then
    CURRENT=$(dpkg-query -W -f='${Version}' messaging-gateway)
    PKG_MGR=apt
elif command -v rpm >/dev/null && rpm -q messaging-gateway >/dev/null 2>&1; then
    CURRENT=$(rpm -q --queryformat '%{VERSION}' messaging-gateway)
    PKG_MGR=dnf
else
    log "messaging-gateway not installed via apt or rpm; check your package manager or vendor instructions."
    exit 0
fi
log "Detected: messaging-gateway=$CURRENT (manager=$PKG_MGR)"

# 2. Backup config
BACKUP=/var/backups/messaging-gateway-$(date +%Y%m%d-%H%M)
mkdir -p "$BACKUP"
for d in /etc/messaging-gateway /etc/${pkg%%-*} ; do
    [ -d "$d" ] && cp -a "$d" "$BACKUP/" && log "Backed up $d to $BACKUP"
done

# 3. Upgrade
if [ "$PKG_MGR" = apt ]; then
    sudo apt-get update -y
    sudo apt-get install --only-upgrade -y messaging-gateway
else
    sudo dnf upgrade --security -y messaging-gateway
fi

# 4. Verify
if [ "$PKG_MGR" = apt ]; then
    NEW=$(dpkg-query -W -f='${Version}' messaging-gateway)
else
    NEW=$(rpm -q --queryformat '%{VERSION}' messaging-gateway)
fi
log "After upgrade: $NEW"

# Optionally compare against <patched-version> with dpkg --compare-versions or sort -V
log "Done. Restart the affected service if the package install did not."

If you can't patch immediately

These are runnable hardening commands. They reduce blast radius but they're not a replacement for the vendor patch.

Rate-limit and log the affected endpoint at the reverse proxy


limit_req_zone $binary_remote_addr zone=admin:10m rate=10r/m;
location /<vulnerable-path> {
    limit_req zone=admin burst=5 nodelay;
    access_log /var/log/nginx/admin-access.log combined;
    proxy_pass http://backend;
}

How to verify the fix worked

Run the version probe again and confirm the running build matches the Fixed in row above.


# Confirm the running build matches the patched version listed by the vendor
# Example for Linux package installs:
dpkg -l | grep -i "messaging"   # Debian/Ubuntu
rpm -qa | grep -i "messaging"   # RHEL/CentOS/Rocky

Expected output: the package version should meet or exceed the patched build.

Then re-run any vulnerability scanner you used previously and confirm the finding for CVE-2017-6327 has cleared. Sweep your logs for the indicators of compromise listed in the vendor or CISA advisory, especially if the system was internet-reachable during the disclosure window.

Frequently asked questions

Is CVE-2017-6327 being actively exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog, which means in-the-wild exploitation has been observed and confirmed.

How severe is CVE-2017-6327?

CVSS rates it 8.8 (High). Use that score to set your patch priority next to the other items in your queue.

Do I have to take Messaging Gateway offline to apply the patch?

It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.

What if my vulnerability scanner still flags CVE-2017-6327 after I patch?

Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.

References

*Written by Sai Kiran Pandrala on 2026-05-25. Sourced from the official vendor advisory, the NVD record, and the CISA KEV listing. Always confirm against the vendor advisory before applying changes in production.*