`challenge.7` contains a single txt file `password.txt` which we are able to extract
```Scanning the drive for archives:1 file, 153628 bytes (151 KiB)
Listing archive: challenge.7z
--Path = challenge.7zType = 7zPhysical Size = 153628Headers Size = 130Method = LZMA2:12Solid = -Blocks = 1
   Date      Time    Attr         Size   Compressed  Name------------------- ----- ------------ ------------  ------------------------2020-10-02 11:00:07 ....A          486          162  password.txt------------------- ----- ------------ ------------  ------------------------2020-10-02 11:00:07                486          162  1 files
```
```$ cat password.txt         _                                 _   _               __ _                __ _(_)_   _____     _ __ ___   ___   | |_| |__   ___     / _| | __ _  __ _   / _` | \ \ / / _ \   | '_ ` _ \ / _ \  | __| '_ \ / _ \   | |_| |/ _` |/ _` | | (_| | |\ V /  __/   | | | | | |  __/  | |_| | | |  __/   |  _| | (_| | (_| |  \__, |_| \_/ \___|___|_| |_| |_|\___|___\__|_| |_|\___|___|_| |_|\__,_|\__, |  |___/           |_____|            |_____|           |_____|           |___/ 
```
seems like password is `give_me_the_flag` , next we notice that the file is actually pretty huge given it contains only a single text file. we inspect it using xxd and observe that there actually is another 7zip archive after the compressed txt file at `000000c0` we see ` 377a bcaf 271c 0004`
```00000000: 377a bcaf 271c 0004 708d 625c 9a57 0200  7z..'...p.b\.W..00000010: 0000 0000 6200 0000 0000 0000 2d63 7183  ....b.......-cq.00000020: e001 e500 9a5d 0010 6a93 c41b 8adf d95e  .....]..j......^00000030: 8def 6644 bb1e 6f47 7fac 44e9 f525 0206  ..fD..oG..D..%..00000040: 0bc6 079f a0ea f5a0 9cbd cdc0 8be3 d293  ................00000050: 9ab9 4f92 2b15 189e c933 12f8 79b2 3c71  ..O.+....3..y.<q00000060: e045 4705 fbd8 2345 da45 629a 5541 b8bb  .EG...#E.Eb.UA..00000070: 8aab d398 38ce b63d 5497 a2b2 6d6d f680  ....8..=T...mm..00000080: 795f 0af1 7538 07e4 def1 2598 d88b b812  y_..u8....%.....00000090: a660 677f 89ca b60e 21a3 e035 8335 5ab3  .`g.....!..5.5Z.000000a0: 2d84 56ff 367d 5975 c7d1 5ea6 6809 c22f  -.V.6}Yu..^.h../000000b0: 1dad 936b 7be6 37dd 9cc2 cf8c bec1 9480  ...k{.7.........000000c0: 0000 377a bcaf 271c 0004 21f2 c54d b356  ..7z..'...!..M.V000000d0: 0200 0000 0000 2500 0000 0000 0000 8dc1  ......%.........000000e0: be36 6772 c955 3e26 ea1f dc4f 7570 8e55  .6gr.U>&...Oup.U000000f0: 0253 1e28 ea7d dce8 f2e8 3c3a 9ea5 b5f3  .S.(.}....<:....00000100: c1c2 27c6 7f3e c17d 09a2 0954 d00e 5df2  ..'..>.}...T..].00000110: 55e6 2cf8 61cc 4835 ff5d f689 daba 118e  U.,.a.H5.]......00000120: 7174 d3bc 1e25 9805 7e54 aef3 57c7 b20d  qt...%..~T..W...00000130: 28b9 40a2 dc44 1790 847f 29fd 55a9 ecca  ([email protected]....).U...00000140: 6222 c19b 7a84 537b 4f3e 467d 5d41 6920  b"..z.S{O>F}]Ai 00000150: 8d1b edc3 9c84 17d0 ad56 6eb2 69bd 23a1  .........Vn.i.#.
```
 we remove everything before these values to get a new archive.  ``` Scanning the drive for archives:1 file, 153434 bytes (150 KiB)
Listing archive: cutted.7z
--Path = cutted.7zType = 7zWARNINGS:There are data after the end of archivePhysical Size = 153336Tail Size = 98Headers Size = 4024Method = LZMA2:192k 7zAESSolid = +Blocks = 1
   Date      Time    Attr         Size   Compressed  Name------------------- ----- ------------ ------------  ------------------------2020-10-02 13:31:21 D....            0            0  part22020-10-02 12:12:15 ....A           46       149312  flag.txt2020-10-02 13:31:04 ....A          564               part2/part2_0.7z2020-10-02 13:31:04 ....A          751               part2/part2_1.7z2020-10-02 13:31:04 ....A          350               part2/part2_10.7z2020-10-02 13:31:08 ....A          189               part2/part2_100.7z2020-10-02 13:31:08 ....A          539               part2/part2_101.7z2020-10-02 13:31:08 ....A          446               part2/part2_102.7z....... ```  we see the `flag.txt` in the archive and also `part2` folder which is part of the next  chall. when we try to extract the flag we are asked for a password which is `give_me_the_flag` from the `password.txt` we extracted earlier  ``` $ cat flag.txt tstlss{next_header_offset_is_a_nice_feature}
 ```