[UNIX] ekg Insecure Temporary Files Creation Vulnerability

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ekg Insecure Temporary Files Creation Vulnerability
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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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