But reputation alone is not evidence of legitimacy.<\/p>\n
That assumption is where many investigations fail.<\/p>\n
Phase 1:- Identifying the Traffic\u00a0Pattern<\/h3>\n
The first step was to analyze the raw web logs. Instead of normal user navigation, we observed direct endpoint requests with highly structured patterns:<\/p>\n
\/a
\/aa
\/ab
\/admin
\/backup
\/config
\/.env<\/p>\n
This behavior did not resemble human browsing. There were no CSS requests, no image loads, no JavaScript assets, and no sequential page navigation. Instead, the requests targeted potential sensitive endpoints directly.<\/p>\n
One path in particular stood out:\u00a0\/.env.<\/p>\n
In modern web applications,\u00a0.env Files often store environment configuration data, such\u00a0as:<\/p>\n
- \n
- Database credentials<\/li>\n
- API tokens<\/li>\n
- SMTP configuration<\/li>\n
- Encryption secrets<\/li>\n<\/ul>\n
If exposed due to misconfiguration, this file alone can lead to full system compromise.<\/p>\n
The server returned HTTP 400 for this request, which indicated no exposure. However, the intent behind the request was clear: this was reconnaissance.<\/p>\n
Phase 2:- Verifying the Source Infrastructure<\/h3>\n
To better understand the origin of the traffic, we performed a reverse DNS\u00a0lookup:<\/p>\n
![\"\"](\"https:\/\/cdn-images-1.medium.com\/max\/601\/1*ZxlKhf2lsyexwwXSDYXraQ.png\")
<\/figure>\nThis was a critical discovery.<\/p>\n
The IP was not associated with Googlebot. It was not a crawler IP resolving to googlebot.com. Instead, it resolved to a googleusercontent.com domain, a strong indicator of Google Cloud Compute Engine infrastructure<\/strong>.<\/p>\n
This meant the traffic originated from a rented virtual machine inside Google\u00a0Cloud.<\/p>\n
In other words, the infrastructure belonged to Google, but the activity did\u00a0not.<\/p>\n
Why Cloud Infrastructure Is Commonly Used for Reconnaissance<\/h3>\n
Modern attackers rarely operate from suspicious home networks. They leverage public cloud platforms because cloud environments provide:<\/p>\n
- \n
- Clean IP reputation<\/li>\n
- High bandwidth<\/li>\n
- Easy deployment and\u00a0teardown<\/li>\n
- Scalability<\/li>\n
- Global distribution<\/li>\n<\/ul>\n
More importantly, cloud ASN ranges are massive. Blocking an entire Google ASN (such as AS15169 or related allocations) would disrupt legitimate services. That makes cloud-hosted reconnaissance difficult to mitigate using simple IP blocking strategies.<\/p>\n
Phase 3:- Behavioral Analysis vs. User-Agent Trust<\/h3>\n
The HTTP headers showed a completely normal User-Agent string:<\/p>\n
Mozilla\/5.0 (Windows NT 10.0; Win64; x64) Chrome\/120.0<\/pre>\n
If analysis stopped at this point, the traffic might have been dismissed as legitimate.<\/p>\n
However, deeper behavioral analysis revealed:<\/p>\n
- \n
- No static asset retrieval<\/li>\n
- No session cookie\u00a0reuse<\/li>\n
- No referrer\u00a0chain<\/li>\n
- No realistic timing\u00a0gaps<\/li>\n
- Sequential endpoint\u00a0probing<\/li>\n
- Sustained high request\u00a0rate<\/li>\n<\/ul>\n
User-Agent strings are trivial to spoof. A single line of code in Python, Go, or curl can replicate any browser signature. Behavioral patterns, however, are far more difficult to fake convincingly.<\/p>\n
The mismatch between declared identity (browser) and actual behavior (automated probing) confirmed the activity was scripted.<\/p>\n
Phase 4: Cross-System Correlation<\/h3>\n
While investigating web logs, we correlated events across additional security layers. On the F5 BIG-IP VPN appliance, we observed repeated\u00a0entries:<\/p>\n
tmm: ssl handshake failed<\/pre>\n
The VPN portal was publicly accessible, meaning external systems could attempt TLS negotiations freely. SSL handshake failures in this context may indicate:<\/p>\n
- \n
- TLS version\u00a0probing<\/li>\n
- Cipher suite fingerprinting<\/li>\n
- Malformed ClientHello packets<\/li>\n
- Automated vulnerability scanning\u00a0tools<\/li>\n<\/ul>\n
When timestamps were aligned, we observed overlap\u00a0between:<\/p>\n
- \n
- Web application enumeration<\/li>\n
- VPN handshake failures<\/li>\n
- Google Cloud\u2013based IP\u00a0ranges<\/li>\n<\/ul>\n
This suggested infrastructure mapping activity rather than isolated web\u00a0probing.<\/p>\n
Classification: Reconnaissance, Not Exploitation<\/h3>\n
At this point, we did not\u00a0observe:<\/p>\n
- \n
- Successful authentication<\/li>\n
- SQL injection payloads<\/li>\n
- Credential brute-force attempts<\/li>\n
- Data exfiltration<\/li>\n
- Exposed sensitive files<\/li>\n<\/ul>\n
However, this activity aligns strongly with MITRE ATT&CK Technique T1595 Active Scanning<\/strong>.<\/p>\n
Reconnaissance is often the quietest phase of an attack lifecycle. It is the phase where adversaries map exposed surfaces, measure response behavior, and test configuration weaknesses before attempting exploitation.<\/p>\n
Detecting reconnaissance early reduces downstream risk significantly.<\/p>\n
Why IP Blocking Alone Is Insufficient<\/h3>\n
Blocking the identified IP would have been simple. However, cloud infrastructure allows near-instant redeployment. An attacker can destroy a virtual machine and launch another in minutes, often within the same IP\u00a0range.<\/p>\n
Instead of relying solely on IP-based mitigation, we implemented behavior-based controls:<\/p>\n
- \n
- Rate limiting for abnormal request\u00a0bursts<\/li>\n
- WAF rules blocking direct access to sensitive files<\/li>\n
- Alerts for high 404 response\u00a0ratios<\/li>\n<\/ul>\n
Key Lessons from This Investigation<\/h3>\n
- \n
- User-Agent strings cannot be trusted\u00a0alone.<\/li>\n
- Cloud-hosted reconnaissance is increasingly common.<\/li>\n
- Early detection of reconnaissance improves overall security\u00a0posture.<\/li>\n
- Behavior-based detection outperforms reputation-based filtering.<\/li>\n<\/ol>\n
The most important takeaway is simple: modern attacks do not originate from obviously malicious networks. They originate from trusted platforms used legitimately by millions of organizations worldwide.<\/p>\n
<\/p>\n
\nReal Investigation:- How We Traced Google Cloud IP Recon Activity<\/a> was originally published in OSINT Team<\/a> on Medium, where people are continuing the conversation by highlighting and responding to this story.<\/p>","protected":false},"excerpt":{"rendered":"
It Didn\u2019t Look Dangerous at\u00a0First Every SOC analyst knows this feeling.You\u2019re watching dashboards.Logs are flowing.Nothing critical. Nothing red.Then you notice one IP address.It\u2019s not triggering a high-severity alert.It\u2019s not exploiting anything.It\u2019s just persistent.50\u2013100 requests per second.Not a spike.Sustained.That\u2019s when instinct kicks\u00a0in. Introduction:- When \u201cGoogle LLC\u201d Doesn\u2019t Mean\u00a0Safe In security operations, not every investigation starts with … Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":467,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-466","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts\/466","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/comments?post=466"}],"version-history":[{"count":0,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/posts\/466\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/media\/467"}],"wp:attachment":[{"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/media?parent=466"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/categories?post=466"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/quantusintel.group\/osint\/wp-json\/wp\/v2\/tags?post=466"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}