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CVE-2023-20198 PoC — Cisco IOS XE Software 安全漏洞

Source
https://github.com/unsightlyabol/cisco-ios-xe-implant-scanner
Associated Vulnerability
Title:Cisco IOS XE Software 安全漏洞 (CVE-2023-20198)
Description:Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software. We are updating the list of fixed releases and adding the Software Checker. Our investigation has determined that the actors exploited two previously unknown issues. The attacker first exploited CVE-2023-20198 to gain initial access and issued a privilege 15 command to create a local user and password combination. This allowed the user to log in with normal user access. The attacker then exploited another component of the web UI feature, leveraging the new local user to elevate privilege to root and write the implant to the file system. Cisco has assigned CVE-2023-20273 to this issue. CVE-2023-20198 has been assigned a CVSS Score of 10.0. CVE-2023-20273 has been assigned a CVSS Score of 7.2. Both of these CVEs are being tracked by CSCwh87343.
Description
A go-exploit to scan for implanted Cisco IOS XE Systems cve-2023-20198, go-exploit
Readme
# Cisco IOS XE Implant Scanner

On October 23, 2023, with all implants no longer responding to requests to `/webui/logoutconfirm.html`, [Fox-IT](https://github.com/fox-it/cisco-ios-xe-implant-detection) developed a new way to determine if a system is compromised or not. In particular, instead of responding to requests with a redirect to the login, the attacker's implant had logic to return 404 if requested URI contained `%`. So this scanner now sends an HTTP get request like `/Fadf%25`. A system with an implant will return the following payload:

```
<html>
<head><title>404 Not Found</title></head>
<body bgcolor="white">
<center><h1>404 Not Found</h1></center>
<hr><center>nginx</center>
</body>
</html>
<!-- a padding to disable MSIE and Chrome friendly error page -->
<!-- a padding to disable MSIE and Chrome friendly error page -->
<!-- a padding to disable MSIE and Chrome friendly error page -->
<!-- a padding to disable MSIE and Chrome friendly error page -->
<!-- a padding to disable MSIE and Chrome friendly error page -->
<!-- a padding to disable MSIE and Chrome friendly error page -->
```

Usage is the same as before (see "Old Docs" section for more usage info) but we can no longer recover the implant-id.

## Compiling

You can use the makefile to build a docker container:

```
make docker
```

Or, if you have a Go build environment ready to go, just use `make`:

```sh
albinolobster@mournland:~/cisco-ios-xe-implant-scanner$ make
gofmt -d -w implant-scanner.go 
golangci-lint run --fix implant-scanner.go
GOOS=linux GOARCH=arm64 go build -o build/implant-scanner_linux-arm64 implant-scanner.go
```

## Example output for an implanted host

```
./build/implant-scanner -a -v -c -rhost 10.9.49.180
time=2023-10-23T14:33:07.581-04:00 level=STATUS msg="Starting target" index=0 host=10.9.49.180 port=80 ssl=false "ssl auto"=true
time=2023-10-23T14:33:08.782-04:00 level=STATUS msg="Validating IOS XE target" host=10.9.49.180 port=80
time=2023-10-23T14:33:10.115-04:00 level=SUCCESS msg="Target validation succeeded!" host=10.9.49.180 port=80
time=2023-10-23T14:33:10.115-04:00 level=STATUS msg="Running a version check on the remote target" host=10.9.49.180 port=80
time=2023-10-23T14:33:10.624-04:00 level=SUCCESS msg="The target appears to be a vulnerable version!" host=10.9.49.180 port=80
```

## Example output for a host with no implant

```
./build/implant-scanner -a -v -c -rhost 10.9.49.124
time=2023-10-23T14:34:31.207-04:00 level=STATUS msg="Starting target" index=0 host=10.9.49.124 port=80 ssl=false "ssl auto"=true
time=2023-10-23T14:34:31.340-04:00 level=STATUS msg="Validating IOS XE target" host=10.9.49.124 port=80
time=2023-10-23T14:34:31.363-04:00 level=SUCCESS msg="Target validation succeeded!" host=10.9.49.124 port=80
time=2023-10-23T14:34:31.363-04:00 level=STATUS msg="Running a version check on the remote target" host=10.9.49.124 port=80
time=2023-10-23T14:34:31.378-04:00 level=ERROR msg="The target appears to be a patched version." host=10.9.49.124 port=80
```

# Old Docs

Scans for the IOS XE implant as described by [Cisco PSIRT](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-webui-privesc-j22SaA4z) and [Cisco Talos](https://blog.talosintelligence.com/active-exploitation-of-cisco-ios-xe-software/). The scanner will send an HTTP POST request to `/webui/logoutconfirm.html?logon_hash=1` and look for the 18 byte hexstring in response. The scanner output will have a line like this when it finds an implant:

```sh
time=2023-10-17T06:09:02.967-04:00 level=SUCCESS msg=Found implant-id=1a80b7389ccd0a5dab rhost=192.168.1.1 rport=80 ssl=false
```

When no implant is found, the scanner will say something like:

```
{"time":"2023-10-17T06:13:48.241233896-04:00","level":"ERROR","msg":"The target appears to be a patched version.","host":"192.168.1.1","port":80}
```

Note that this isn't indicative of a patched version, only that an implant wasn't found. This is just generic output from [go-exploit](https://github.com/vulncheck-oss/go-exploit)'s version scanner. Because this is built on go-exploit, it supports a variety of scanning functionality. Sample usage follows:

## Scanning One Host

```sh
$ ./build/implant-scanner -rhost 192.168.1.1 -rport 80 -proxy socks5://127.0.0.1:9050 -a -v -c
time=2023-10-17T06:08:59.586-04:00 level=STATUS msg="Starting target" index=0 host=192.168.1.1port=80 ssl=false "ssl auto"=true
time=2023-10-17T06:09:00.882-04:00 level=STATUS msg="Validating IOS XE target" host=192.168.1.1port=80
time=2023-10-17T06:09:02.237-04:00 level=SUCCESS msg="Target validation succeeded!" host=192.168.1.1port=80
time=2023-10-17T06:09:02.237-04:00 level=STATUS msg="Running a version check on the remote target" host=192.168.1.1port=80
time=2023-10-17T06:09:02.967-04:00 level=SUCCESS msg=Found implant-id=1a80b7389ccd0a5dab rhost=192.168.1.1rport=80 ssl=false
time=2023-10-17T06:09:02.967-04:00 level=SUCCESS msg="The target appears to be a vulnerable version!" host=192.168.1.1port=80
```

## Scanning One Host Through a Proxy

```sh
$ ./build/implant-scanner -rhost 192.168.1.1-rport 80 -proxy socks5://127.0.0.1:9050 -a -v -c
time=2023-10-17T06:08:59.586-04:00 level=STATUS msg="Starting target" index=0 host=192.168.1.1port=80 ssl=false "ssl auto"=true
time=2023-10-17T06:09:00.882-04:00 level=STATUS msg="Validating IOS XE target" host=192.168.1.1port=80
time=2023-10-17T06:09:02.237-04:00 level=SUCCESS msg="Target validation succeeded!" host=192.168.1.1port=80
time=2023-10-17T06:09:02.237-04:00 level=STATUS msg="Running a version check on the remote target" host=192.168.1.1port=80
time=2023-10-17T06:09:02.967-04:00 level=SUCCESS msg=Found implant-id=1a80b7389ccd0a5dab rhost=192.168.1.1rport=80 ssl=false
time=2023-10-17T06:09:02.967-04:00 level=SUCCESS msg="The target appears to be a vulnerable version!" host=192.168.1.1port=80
```

## Scanning a File of Hosts and Logging JSON to File

See go-exploit [documentation](https://github.com/vulncheck-oss/go-exploit/blob/main/docs/scanning.md) for a better understanding of the -rhosts-file format.

```sh
$ ./build/implant-scanner -rhosts-file targets -log-json -log-file ./logs/output.json -v -c
$ tail logs/output.json
{"time":"2023-10-17T06:16:07.24555914-04:00","level":"STATUS","msg":"Validating IOS XE Implant target","host":"192.168.1.1","port":443}
{"time":"2023-10-17T06:16:10.363281285-04:00","level":"SUCCESS","msg":"Target validation succeeded!","host":"192.168.1.1","port":443}
{"time":"2023-10-17T06:16:10.363345035-04:00","level":"STATUS","msg":"Running a version check on the remote target","host":"192.168.1.1","port":443}
```
File Snapshot

 [4.0K]  /data/pocs/91e4497a752b2e2a9c88a8a967f77f07963845f9
├── [ 466]  Dockerfile
├── [ 870]  go.mod
├── [4.7K]  go.sum
├── [3.6K]  implant-scanner.go
├── [ 11K]  LICENSE
├── [2.1K]  Makefile
└── [6.5K]  README.md

0 directories, 7 files
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