[UNIX] ekg Insecure Temporary Files Creation Vulnerability

From: SecuriTeam (support_at_securiteam.com)
Date: 07/06/05

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Date: 6 Jul 2005 14:24:26 +0200

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      ekg Insecure Temporary Files Creation Vulnerability
    ------------------------------------------------------------------------

    SUMMARY

     <http://dev.null.pl/ekg> ekg is "a Gadu-Gadu client". ekg creates
    temporary files in an insecure way, allowing local attackes to gain
    elevated privileges via a symblink attack.

    DETAILS

    Vulnerable Systems:
     * ekg versions released before 2005-06-05

    The vulnerability is caused due to temporary files being created
    insecurely. This can be exploited via a symlink attack, and in turn create
    and/or overwrite arbitrary files with the privileges of the user running
    the affected script.

    Vulnerable code:
    In contrib/scripts/linki.py
    95 def czyjest ():
    96 if os.path.exists('/tmp/rmrmg_ekg_url'):
    97 wejsc= open ('/tmp/rmrmg_ekg_url')
    98 file = wejsc.readlines()
    99 dlug=len(file)
    100 wejsc.close()
    101 #ekg.printf("generic", "liczno %d" %(dlug))
    102 return file
    103 else:
    104 return 0

    Then
    35 def handle_keypress(meta, key):
    36 if key == 269:
    37 ekg.printf("generic", "wci nieto F5")
    38 nurl=czyjest()
    39 if nurl == 0:
    40 ekg.printf("generic", "nie ma zadnego adresu URL")
    41 else:
    42 dlug=len(nurl)
    43 if dlug == 1:
    44 ekg.printf("generic", "otwieram %s w nowej zak adce"
    %(nurl[0]))
    45 os.system("MozillaFirebird -remote 'openURL(%s,new-tab)'"
    %(nurl[0]))
    46 os.system('rm /tmp/rmrmg_ekg_url')
    47 else:
    48 ekg.printf("generic", "link w mam %d" %(dlug))
    49 wielejest(nurl)
    50 ekg.printf("generic", "otwieram %s w nowej zak adce"
    %(nurl[0]))
    51 os.system("MozillaFirebird -remote 'openURL(%s, new-tab)'"
    %(nurl[0]))
    52 elif key == 270:
    53 ekg.printf("generic", "wcisni to F6")
    54 nurl=czyjest()
    55 if nurl == 0:
    56 ekg.printf("generic", "nic nie moge skasowa - nie mazadnego
    adresu URL")
    57 else:
    58 dlug=len(nurl)
    59 if dlug == 1:
    60 ekg.printf("generic", "kasuje adres %s" %(nurl[0]))
    61 os.system('rm /tmp/rmrmg_ekg_url')
    62 else:
    63 ekg.printf("generic", "jest wiele link w")
    64 wielejest(nurl)
    65 ekg.printf("generic", "kasuje pierwszy czyli: %s"%(nurl[0]))
    66 elif key == 271:
    67 ekg.printf("generic", "wcisni to F7")
    68 nurl=czyjest()
    69 if nurl == 0:
    70 ekg.printf("generic", "nie ma zadnego adresu URL")
    71 else:
    72 dlug=len(nurl)
    73 if dlug == 1:
    74 ekg.printf("generic", "otwieram %s w nowym oknie"%(nurl[0]))
    75 os.system("MozillaFirebird %s" %(nurl[0]))
    76 os.system('rm /tmp/rmrmg_ekg_url')
    77 else:
    78 ekg.printf("generic", "link w mam %d" %(dlug))
    79 wielejest(nurl)
    80 ekg.printf("generic", "otwieram %s w nowym oknie"%(nurl[0]))
    81 elif key == 272:
    82 ekg.printf("generic", "wcisni to F8")
    83 nurl=czyjest()
    84 ekg.printf("generic", "F5 - otwiera w nowej zak adce; F7 wnowym
    oknie, a F6 kasuje, wszystko tyczy si pierwszej po zycji zlisty")
    85 if nurl == 0:
    86 ekg.printf("generic", "nie ma zadnego adresu URL")
    87 else:
    88 dlug=len(nurl)
    89 ekg.printf("generic", "link w mam %d oto one:" %(dlug))
    90 for po in nurl:
    91 ekg.printf("generic", "%s" %(po))
    92 return 1

    CVE Information:
     <http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-1916>
    CAN-2005-1916

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:exploits@zataz.net> ZATAZ
    Audits.
    The original article can be found at:
    <http://www.zataz.net/adviso/ekg-06062005.txt>
    http://www.zataz.net/adviso/ekg-06062005.txt
    The original article can be found at:
    <http://bugs.gentoo.org/show_bug.cgi?id=94172>
    http://bugs.gentoo.org/show_bug.cgi?id=94172

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