NSFOCUS SA2003-02: Solaris lpq Stack Buffer Overflow Vulnerability

2003-04-01T00:00:00
ID SECURITYVULNS:DOC:4325
Type securityvulns
Reporter Securityvulns
Modified 2003-04-01T00:00:00

Description

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NSFOCUS Security Advisory(SA2003-02)

Topic: Solaris lpq Stack Buffer Overflow Vulnerability

Release Date: 2003-3-31

CVE CAN ID: CAN-2003-0091

Affected system:

Sun Solaris 2.5.1 (SPARC/x86) Sun Solaris 2.6 (SPARC/x86) Sun Solaris 7 (SPARC/x86)

Summary:

NSFOCUS Security Team has found a buffer overflow vulnerability in lpq, an application in Sun Solaris system. Exploiting the vulnerability local attackers could gain root privilege.

Description:

lpq, which is used to display the contents in printing queue, is a command in SunOS/BSD compatible package.By default suid root bit is set to it. Because valid bound check has not been implemented when handling the data provided by users, attackers could cause a fixed stack buffer to overflow. By carefully crafting overflow data attackers could run arbitrary code with root privilege.

Actually /usr/ucb/lpq is a symbol link to /usr/bin/lpstat. lpstat will operate according to the program names during the calling. If "lpq", it will operate in BSD style, or it will operate in System V style. The bsd_queue() function in lpq will call strcat() to copy the data provided by users to a buffer the size of which is fixed. Because the length of the copied data has not been checked, if an attacker provides a over-long string, he/she will cause a stack buffer overflow. By overwriting the returning addresses and other data in the stack, local attackers could gain root privilege.

Solaris 8/9 uses strlcat() to implement string copy, so it avoids buffer overflow and therefore is not vulnerable to the issue.

Workaround:

NSFOCUS suggests to disable suid root attribute of lpstat(lpq) temporarily: # chmod a-s /usr/bin/lpstat

Vendor Status:

2002-12-11 Informed the vendor. 2002-12-13 The vendor confirmed the vulnerability. 2003-03-31 The vendor released a Sun Alert and patches for this issue.

The Sun Alert is available at: http://sunsolve.Sun.COM/pub-cgi/retrieve.pl?doc=fsalert/52443

The patches are:

Solaris 2.6 106235-12 Solaris 2.6_x86 106236-12 Solaris 7 107115-12 Solaris 7_x86 107116-12

Additional Information:

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2003-0091 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. Candidates may change significantly before they become official CVE entries.

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Copyright 1999-2003 NSFOCUS. All Rights Reserved. Terms of use.

NSFOCUS Security Team <security@nsfocus.com> NSFOCUS INFORMATION TECHNOLOGY CO.,LTD (http://www.nsfocus.com)

PGP Key: http://www.nsfocus.com/homepage/research/pgpkey.asc Key fingerprint = F8F2 F5D1 EF74 E08C 02FE 1B90 D7BF 7877 C6A6 F6DA

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