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-----BEGIN PGP SIGNED MESSAGE----- |
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Hash: SHA1 |
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|
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- - - --------------------------------------------------------------------- |
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GENTOO LINUX SECURITY ANNOUNCEMENT 200304-08 |
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- - - --------------------------------------------------------------------- |
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|
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PACKAGE : pptpd |
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SUMMARY : buffer overflow |
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DATE : 2003-04-28 09:22 UTC |
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EXPLOIT : remote |
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VERSIONS AFFECTED : <pptpd-1.1.3.20030429 |
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FIXED VERSION : >=pptpd-1.1.3.20030429 |
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CVE : CAN-2003-0213 |
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|
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- - - --------------------------------------------------------------------- |
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|
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- - From advisory: |
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|
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"PPTP packet header contain 16bit length which specifies the full size of |
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the packet: |
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|
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bytes_this = read(clientFd, packet + bytes_ttl, 2 - bytes_ttl); |
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// ... |
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bytes_ttl += bytes_this; |
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// ... |
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length = htons(*(u_int16_t *) packet); |
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if (length > PPTP_MAX_CTRL_PCKT_SIZE) { |
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// abort |
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} |
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|
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Looks good so far, except: |
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|
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bytes_this = read(clientFd, packet + bytes_ttl, length - bytes_ttl); |
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|
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If given length was 0 or 1, the "length - bytes_ttl" result is -1 or -2, |
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which means that it reads unlimited amount of data from client into |
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"packet", which is a buffer located in stack. |
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|
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The exploitability only depends on if libc allows the size parameter to be |
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larger than SSIZE_MAX bytes. GLIBC does, Solaris and *BSD don't." |
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|
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Read the full advisory at: |
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http://marc.theaimsgroup.com/?l=bugtraq&m=104994375011406&w=2 |
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|
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SOLUTION |
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|
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It is recommended that all Gentoo Linux users who are running |
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net-dialup/pptpd upgrade to pptpd-1.1.3.20030409 as follows: |
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|
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emerge sync |
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emerge pptpd |
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emerge clean |
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|
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- - - --------------------------------------------------------------------- |
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aliz@g.o - GnuPG key is available at http://cvs.gentoo.org/~aliz |
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- - - --------------------------------------------------------------------- |
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-----BEGIN PGP SIGNATURE----- |
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Version: GnuPG v1.2.1 (GNU/Linux) |
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=hi8d |
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