Detect Cisco Catalyst SD-WAN Manager Storing Passwords in a Recoverable Format (CVE-2026-20128) in Google Chronicle
CVE-2026-20128 affects Cisco Catalyst SD-WAN Manager and involves storing passwords in a recoverable format (CWE-257). An attacker with local or network access to the SD-WAN Manager may be able to extract plaintext or weakly-obfuscated credentials from configuration files, databases, or memory. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. Successful exploitation could lead to credential theft enabling lateral movement, further network compromise, or full SD-WAN infrastructure takeover.
MITRE ATT&CK
YARA-L Detection Query
rule cve_2026_20128_sdwan_credential_exposure {
meta:
author = "df00tech Detection Engineering"
description = "Detects CVE-2026-20128 exploitation: credential extraction from Cisco Catalyst SD-WAN Manager"
severity = "HIGH"
cve = "CVE-2026-20128"
mitre_attack = "T1552.001"
events:
(
$e.metadata.event_type = "FILE_OPEN"
and re.regex($e.target.file.full_path, `(?i)(/etc/viptela|/opt/nms|vmanage|\.viptela)`)
)
or
(
$e.metadata.event_type = "PROCESS_LAUNCH"
and re.regex($e.target.process.command_line, `(?i)(sqlite3|strings|python|perl|ruby).*(?:password|passwd|credential|secret|vmanage)`)
)
or
(
$e.metadata.event_type = "NETWORK_CONNECTION"
and $e.target.port in (8443, 8444)
and re.regex($e.principal.process.command_line, `(?i)(curl|wget|python|ruby)`)
)
condition:
$e
}Chronicle YARA-L rule for CVE-2026-20128 detecting three exploitation patterns: direct vManage configuration file access, credential-scraping process invocation, and suspicious programmatic connections to SD-WAN Manager API ports.
Data Sources
Required Tables
False Positives & Tuning
- Authorized backup and archiving tools accessing vManage configuration directories
- Scripted monitoring solutions connecting to vManage REST API on port 8443
- Cisco support engineers running remote diagnostic commands
Other platforms for CVE-2026-20128
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1vManage SQLite Credential Database Direct Query
Expected signal: Process creation event for sqlite3 with command line containing /opt/nms/db or credential-related terms; file access event on vManage database path
- Test 2Grep for Passwords in vManage Configuration Directory
Expected signal: Process launch event for grep with arguments targeting /etc/viptela or similar paths and containing password-related search terms
- Test 3Unauthorized vManage REST API Credential Extraction via Python
Expected signal: Process launch event for python3 with command line containing the vManage management port (8443) and credential/user-related API path; NetworkConnectionIP4 event to localhost:8443
- Test 4strings Utility Against vManage Process Memory or Binary
Expected signal: Process creation for 'strings' with /proc/<pid>/exe or a vManage binary path as argument; subsequent grep process with credential search terms
References (4)
- https://www.cisa.gov/news-events/directives/ed-26-03-mitigate-vulnerabilities-cisco-sd-wan-systems
- https://www.cisa.gov/news-events/directives/supplemental-direction-ed-26-03-hunt-and-hardening-guidance-cisco-sd-wan-systems
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-authbp-qwCX8D4v
- https://nvd.nist.gov/vuln/detail/CVE-2026-20128
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