CVE-2026-34909 Sumo Logic CSE · Sumo

Detect Ubiquiti UniFi OS Path Traversal Exploitation Attempt in Sumo Logic CSE

Detects exploitation attempts targeting CVE-2026-34909, a path traversal vulnerability (CWE-22) in Ubiquiti UniFi OS. This vulnerability is actively exploited in the wild (CISA KEV) and allows attackers to traverse directory boundaries to access sensitive files or execute unauthorized actions on UniFi network management devices.

MITRE ATT&CK

Tactic
Initial Access Defense Evasion Discovery

Sumo Detection Query

Sumo Logic CSE (Sumo)
sql 
_sourceCategory=network/proxy OR _sourceCategory=network/ids OR _sourceCategory=firewall
| parse "* * * *" as src_ip, dest_ip, dest_port, url nodrop
| urldecode(url) as decoded_url
| where dest_port in ("80", "443", "8080", "8443")
| where url matches "*../*" or url matches "*..%2F*" or url matches "*..%5C*"
   or url matches "*%2e%2e%2f*" or url matches "*%252f*"
   or decoded_url matches "*../../../*"
   or decoded_url matches "*/etc/passwd*"
   or decoded_url matches "*/data/unifi*"
| count as attempt_count by src_ip, dest_ip, dest_port, url, decoded_url
| sort by attempt_count desc
critical severity medium confidence

Sumo Logic query for detecting path traversal attempts against UniFi OS management interfaces across proxy and firewall log sources.

Data Sources

Sumo Logic proxy logsSumo Logic firewall logsSumo Logic IDS logs

Required Tables

network/proxynetwork/idsfirewall

False Positives & Tuning

  • Legitimate network management tools performing automated configuration backups with file-path-like parameters
  • Security scanners running scheduled assessments against UniFi infrastructure
  • Web crawlers or bots probing management interfaces with malformed requests
  • Internal monitoring agents querying UniFi API endpoints that contain encoded path components

Other platforms for CVE-2026-34909

Microsoft Sentinel (KQL) Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

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.

  1. Test 1Basic Path Traversal Probe Against UniFi OS Management Interface

    Expected signal: HTTP request log entry on the UniFi device or upstream proxy showing the traversal sequence in the URL. Network flow record for destination port 8443 from the test source IP.

  2. Test 2URL-Encoded Path Traversal Bypass Attempt

    Expected signal: HTTP request containing URL-encoded traversal sequence `%2e%2e%2f` captured in proxy or IDS logs. Detection should fire on both raw and decoded URL fields.

  3. Test 3Double-Encoded Traversal Sequence for WAF Bypass Simulation

    Expected signal: HTTP request log entry containing `%252f` in the URL, captured by proxy or WAF logs upstream of the UniFi device.

  4. Test 4Automated Path Traversal Scan Using Nuclei

    Expected signal: Multiple rapid HTTP requests to port 8443 containing various traversal payloads in quick succession, consistent with scanner behavior. Source IP generates a burst of traversal-pattern requests within seconds.

Last updated: 2026-06-24 Research depth: standard
References (4)

Response Playbook

Triage

  1. Identify the source IP initiating the path traversal request and determine if it is internal, external, or associated with a known threat actor or scanning service using threat intelligence enrichment.
  2. Examine the full URL payload to determine the targeted file path — prioritize alerts where the traversal resolves to sensitive UniFi OS files such as /data/unifi/db/, /etc/shadow, /etc/passwd, or configuration directories containing credentials.
  3. Check the HTTP response code returned for the traversal request: a 200 OK response strongly indicates successful exploitation and requires immediate escalation; 4xx responses suggest blocked or failed attempts.
  4. Correlate the source IP against firewall and authentication logs to determine if prior access to the UniFi management interface was attempted, succeeded, or if any administrative accounts were accessed around the same timeframe.
  5. Identify all UniFi OS devices in the environment and their firmware versions to determine patch status and scope of exposure.

Containment

  1. If exploitation is confirmed (HTTP 200 response to traversal payload), immediately isolate the affected UniFi OS device from the network by disabling its uplink or applying an emergency ACL to block all management-plane traffic except from trusted admin hosts.
  2. Block the attacker source IP(s) at the perimeter firewall and any upstream ISP-managed ACLs. If the attack originates from a cloud provider or residential ISP, consider temporarily blocking the ASN at the perimeter while investigation proceeds.
  3. Revoke all active sessions on the UniFi management interface and force re-authentication for all administrator accounts. Rotate UniFi site admin credentials and any API tokens or SSH keys stored on the device.

Evidence Collection

  1. Export and preserve UniFi OS system logs from /var/log/ and application logs from /data/unifi/logs/ before any remediation or reboot, as logs may be overwritten. Archive to a forensically sound, write-protected location.
  2. Capture a memory image of the UniFi OS device if supported by the hardware platform, to identify any in-memory implants or post-exploitation code loaded after the traversal.
  3. Collect network packet captures from the span port or inline TAP covering the period of the attack to reconstruct the full HTTP session and identify what files were accessed or exfiltrated.

Escalation Criteria

  • !Escalate immediately to incident response if the HTTP response to the traversal payload was 200 OK, indicating successful file read or code execution — treat this as an active compromise of the network management plane.
  • !Escalate if the traversal payload targeted credential stores, VPN configuration files, or network topology data, as the attacker may be staging for lateral movement into the broader network infrastructure.

Investigation Guide

Related Techniques

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Forensic Artifacts

  • >UniFi OS HTTP access logs at /var/log/unifi/ or equivalent path showing traversal-containing request URLs with timestamps and source IPs
  • >File system access timestamps (atime) on sensitive files such as /etc/passwd, /etc/shadow, /data/unifi/db/config.db that may have been read via the traversal
  • >Authentication logs showing any new administrator accounts created or existing account privilege changes following the traversal event
  • >Network flow records capturing the full TCP session between the attacker and the UniFi management interface port

Tuning Guidance

Reduce false positives by scoping the detection to known UniFi OS device IP ranges or subnets hosting network management infrastructure. Add a whitelist of authorized scanner IPs (Nessus, Qualys, internal red team NAT egress) to suppress known-good traversal traffic. Increase confidence by correlating traversal alerts with HTTP 200 response codes and non-zero response body sizes, which indicate file content was returned. If UniFi devices publish their management FQDN, filter on destination hostname to eliminate unrelated web servers generating noise.

Hunting Queries

Hunt for successful path traversal responses (HTTP 200) against UniFi management ports to identify confirmed exploitation across the environment.

Hunting — KQL
kql 
CommonSecurityLog
| where TimeGenerated >= ago(30d)
| where DestinationPort in (443, 8443, 80, 8080)
| where RequestURL has_any ("../", "..%2F", "..%5C", "%2e%2e")
| where AdditionalExtensions has "responseCode=200" or ResponseCode == 200
| project TimeGenerated, SourceIP, DestinationIP, RequestURL, ResponseCode, BytesReceived
| order by TimeGenerated desc
Hunting — SPL
spl 
index=proxy OR index=network sourcetype IN ("stream:http", "zeek:http", "pan:traffic")
| eval decoded_uri=urldecode(uri)
| where (match(uri, "(\.\./|\.\.%2F|\.\.%5C|%2e%2e)")) AND status=200
| table _time, src_ip, dest_ip, dest_port, decoded_uri, status, bytes_out
| sort -_time

Hunt for lateral movement from compromised UniFi devices by identifying SSH or management-plane connections originating from UniFi OS device IPs following the traversal window.

Hunting — KQL
kql 
let TraversalSources = CommonSecurityLog
| where TimeGenerated >= ago(7d)
| where RequestURL has_any ("../", "..%2F", "..%5C")
| distinct SourceIP;
CommonSecurityLog
| where TimeGenerated >= ago(7d)
| where SourceIP in (TraversalSources)
| where DestinationPort in (22, 3389, 5985, 5986)
| project TimeGenerated, SourceIP, DestinationIP, DestinationPort, RequestURL
Hunting — SPL
spl 
index=firewall OR index=network (dest_port=22 OR dest_port=3389 OR dest_port=5985)
[search index=proxy sourcetype="stream:http" | eval uri=urldecode(uri) | where match(uri, "(\.\./|%2e%2e)") | return src_ip]
| table _time, src_ip, dest_ip, dest_port
| sort -_time

Atomic Red Team Tests

Test 1 Basic Path Traversal Probe Against UniFi OS Management Interface
linux

Sends an HTTP GET request containing a path traversal sequence to the UniFi OS management port to test whether the endpoint is vulnerable to CVE-2026-34909.

Command

bash 
curl -v -k 'https://TARGET_UNIFI_IP:8443/api/s/default/../../../../etc/passwd' -H 'Cookie: unifises=VALID_SESSION_TOKEN'

Cleanup

bash 
No cleanup required; this is a read-only probe with no persistent side effects on the tester's system.

Expected Telemetry

HTTP request log entry on the UniFi device or upstream proxy showing the traversal sequence in the URL. Network flow record for destination port 8443 from the test source IP.

Expected Detection

Alert fires on the path traversal pattern `../../../../etc/passwd` in the request URL. If the device is vulnerable, a 200 response with /etc/passwd contents triggers the confirmed-exploitation hunt query.

Test 2 URL-Encoded Path Traversal Bypass Attempt
linux

Tests double and percent-encoded traversal sequences to verify detection coverage of obfuscated payloads that may bypass naive string matching.

Command

bash 
curl -v -k 'https://TARGET_UNIFI_IP:8443/api/s/default/%2e%2e%2f%2e%2e%2f%2e%2e%2fetc%2fpasswd' -H 'Cookie: unifises=VALID_SESSION_TOKEN'

Cleanup

bash 
No cleanup required.

Expected Telemetry

HTTP request containing URL-encoded traversal sequence `%2e%2e%2f` captured in proxy or IDS logs. Detection should fire on both raw and decoded URL fields.

Expected Detection

Alert fires on decoded URL matching `../../../etc/passwd` pattern, validating that URL decoding is applied before traversal pattern matching in the detection logic.

Test 3 Double-Encoded Traversal Sequence for WAF Bypass Simulation
linux

Uses double-encoded traversal sequences (%252f for /) to simulate a WAF bypass technique commonly observed in active exploitation of path traversal CVEs.

Command

bash 
curl -v -k 'https://TARGET_UNIFI_IP:8443/api/s/default/..%252f..%252f..%252fetc%252fshadow' -H 'Cookie: unifises=VALID_SESSION_TOKEN'

Cleanup

bash 
No cleanup required.

Expected Telemetry

HTTP request log entry containing `%252f` in the URL, captured by proxy or WAF logs upstream of the UniFi device.

Expected Detection

Alert fires on the `%252f` double-encoding pattern in the KQL and SPL queries that explicitly match this bypass variant, confirming detection coverage of advanced obfuscation techniques.

Test 4 Automated Path Traversal Scan Using Nuclei
linux

Runs a targeted Nuclei scan using a path traversal template against the UniFi management interface to simulate what an attacker using automated exploitation tooling would generate.

Command

bash 
nuclei -u https://TARGET_UNIFI_IP:8443 -t path-traversal/ -severity critical,high -o /tmp/unifi_traversal_results.txt -silent

Cleanup

bash 
rm -f /tmp/unifi_traversal_results.txt

Expected Telemetry

Multiple rapid HTTP requests to port 8443 containing various traversal payloads in quick succession, consistent with scanner behavior. Source IP generates a burst of traversal-pattern requests within seconds.

Expected Detection

Alert fires on multiple traversal attempts from the same source IP within a short window. The summarized query output shows AttemptCount elevated above baseline, flagging the scanner IP for investigation.

Related Detections

Tactic Hubs

TA0001Initial AccessTA0005Defense EvasionTA0007Discovery

Related Techniques

T1190Exploit Public-Facing ApplicationT1083File and Directory DiscoveryT1552.001Credentials In FilesT1021.004SSH

Same Tactic: Initial Access

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