# [HIGH] Astro Full-Read SSRF via Host Header Injection

**Source:** Aikido
**Published:** 2026-02-23
**Article:** https://www.aikido.dev/blog/astro-full-read-ssrf-via-host-header-injection

## Threat Profile

Blog Vulnerabilities & Threats Astro Full-Read SSRF via Host Header Injection Astro Full-Read SSRF via Host Header Injection Written by Jorian Woltjer Published on: Feb 23, 2026 ‍ Astro is a JavaScript frontend and backend framework in use by many large organizations for making website development much easier. Recently, one of the agents in our Aikido Attack product identified a medium-severity vulnerability in the server-side implementation of this framework. It made any servers directly access…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-25545`

## MITRE ATT&CK Techniques

- **T1005** — Data from Local System
- **T1539** — Steal Web Session Cookie
- **T1555.003** — Credentials from Web Browsers
- **T1190** — Exploit Public-Facing Application
- **T1195.002** — Compromise Software Supply Chain
- **T1071.001** — Application Layer Protocol: Web Protocols
- **T1133** — External Remote Services

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Astro SSRF (CVE-2026-25545) — Node.js egress fetch for /404.html or /500.html with UA 'node'

`UC_510_4` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=t count min(_time) as firstTime max(_time) as lastTime values(Web.url) as url values(Web.src) as src values(Web.dest) as dest values(Web.http_method) as method values(Web.status) as status from datamodel=Web where (Web.http_user_agent="node" OR Web.http_user_agent="node-fetch*" OR Web.http_user_agent="undici*") (Web.url="*/404.html*" OR Web.url="*/500.html*") Web.http_method=GET by Web.src,Web.dest,Web.site,Web.http_user_agent | `drop_dm_object_name(Web)` | where NOT match(dest,"^(10\.|172\.(1[6-9]|2[0-9]|3[01])\.|192\.168\.|127\.|169\.254\.)") | rename src as astro_server, dest as attacker_host | `security_content_ctime(firstTime)`
```

**Defender KQL:**
```kql
// CVE-2026-25545 — Astro Node server egressing to external host fetching /404.html or /500.html
let astro_hosts = dynamic(["node.exe","node"]);
DeviceNetworkEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName in~ (astro_hosts)
| where RemoteIPType == "Public"
| where ActionType in ("ConnectionSuccess","HttpConnectionInspected","ConnectionAttempt")
| where RemoteUrl has_any ("/404.html","/500.html") or RemotePort in (80, 443)
| where InitiatingProcessCommandLine has_any ("astro","@astrojs/node","dist/server","server/entry.mjs")
| project Timestamp, DeviceName, InitiatingProcessAccountName, InitiatingProcessFileName, InitiatingProcessCommandLine, RemoteIP, RemotePort, RemoteUrl, ActionType
| order by Timestamp desc
```

### Astro SSRF (CVE-2026-25545) — inbound Host header mismatch with 4xx/5xx response (trigger)

`UC_510_5` · phase: **delivery** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=t count min(_time) as firstTime max(_time) as lastTime values(Web.url) as url values(Web.user_agent) as user_agent values(Web.src) as src from datamodel=Web where Web.status IN (404,500) by Web.site,Web.dest,Web.status | `drop_dm_object_name(Web)` | rex field=site "^(?<host_only>[^:]+)" | search NOT host_only IN ("www.example.com","example.com","astro.example.com") | where isnotnull(site) AND site!="-" AND len(site)>0 | `security_content_ctime(firstTime)`
```

### Crypto-wallet file/keystore access by non-wallet process

`UC_CRYPTO_WALLET` · phase: **actions** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Filesystem
    where (Filesystem.file_path="*\Ethereum\keystore\*"
        OR Filesystem.file_path="*\Bitcoin\wallet.dat"
        OR Filesystem.file_path="*\Exodus\exodus.wallet*"
        OR Filesystem.file_path="*\Electrum\wallets\*"
        OR Filesystem.file_path="*\MetaMask\*"
        OR Filesystem.file_path="*\Phantom\*"
        OR Filesystem.file_path="*\Atomic\Local Storage\*")
      AND NOT Filesystem.process_name IN ("MetaMask.exe","Exodus.exe","Atomic.exe","electrum.exe","Bitcoin.exe","Phantom.exe")
    by Filesystem.dest, Filesystem.process_name, Filesystem.file_path, Filesystem.user
| `drop_dm_object_name(Filesystem)`
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where InitiatingProcessAccountName !endswith "$"
| where FolderPath has_any (@"\Ethereum\keystore\", @"\Bitcoin\", @"\Exodus\", @"\Electrum\wallets\", @"\MetaMask\", @"\Phantom\", @"\Atomic\Local Storage\")
| where InitiatingProcessFileName !in~ ("MetaMask.exe","Exodus.exe","Atomic.exe","electrum.exe","Bitcoin.exe","Phantom.exe")
| project Timestamp, DeviceName, InitiatingProcessAccountName, InitiatingProcessFileName, FolderPath, FileName, ActionType
```

### Infostealer — non-browser process accessing browser cookie/login DBs

`UC_BROWSER_STEALER` · phase: **actions** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Filesystem
    where (Filesystem.file_path="*\Google\Chrome\User Data\*\Login Data*"
        OR Filesystem.file_path="*\Google\Chrome\User Data\*\Cookies*"
        OR Filesystem.file_path="*\Microsoft\Edge\User Data\*\Login Data*"
        OR Filesystem.file_path="*\Mozilla\Firefox\Profiles\*\logins.json*"
        OR Filesystem.file_path="*\Mozilla\Firefox\Profiles\*\cookies.sqlite*")
      AND NOT Filesystem.process_name IN ("chrome.exe","msedge.exe","firefox.exe","brave.exe","opera.exe")
    by Filesystem.dest, Filesystem.process_name, Filesystem.file_path, Filesystem.user
| `drop_dm_object_name(Filesystem)`
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where InitiatingProcessAccountName !endswith "$"
| where FolderPath has_any (@"\Google\Chrome\User Data\", @"\Microsoft\Edge\User Data\", @"\Mozilla\Firefox\Profiles\")
| where FileName in~ ("Login Data","Cookies","logins.json","cookies.sqlite")
| where InitiatingProcessFileName !in~ ("chrome.exe","msedge.exe","firefox.exe","brave.exe","opera.exe")
| project Timestamp, DeviceName, InitiatingProcessAccountName, InitiatingProcessFileName, FolderPath, FileName, ActionType
```

### Trusted vendor binary / installer launching unusual children

`UC_SUPPLY_CHAIN` · phase: **exploit** · confidence: **Medium**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.parent_process_name IN ("setup.exe","installer.exe","update.exe")
      AND Processes.process_name IN ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
    by Processes.dest, Processes.user, Processes.parent_process_name, Processes.process_name, Processes.process
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where InitiatingProcessFileName in~ ("setup.exe","installer.exe","update.exe")
| where FileName in~ ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, FileName, ProcessCommandLine
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-25545`


## Why this matters

Severity classified as **HIGH** based on: CVE present, 6 use case(s) fired, 7 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.