3814 : Multiple Unix Vendor passwd Malformed ulimit /etc/passwd Manipulation
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Views This Week	Views All Time	Added to OSVDB	Last Modified	Modified (since 2008)	Percent Complete
17	864	over 8 years ago	over 2 years ago	1 times	90%

Timeline

Disclosure Date	Exploit Publish Date
1989-01-31	1989-01-31

Keywords

return, call, function

Description

passwd contains an implementation flaw that may allow a local denial of service. The issue is triggered when the 'passwd' command is used in an environment with a very small ulimit value. If /etc/passwd is larger than the ulimit, use of the 'passwd' command will result in a truncated /etc/passwd file. If ulimit was set to 0 the /etc/passwd file will be empty, which will invalidate all password authentication attempts, and result in a loss of availability.

Classification

Location: Local Access Required
Attack Type: Authentication Management
Impact: Loss of Availability
Exploit: Exploit Public
Disclosure: OSVDB Verified

Solution

Modern implementations of the 'passwd' utility perform adequate checks to avoid this vulnerabilitu. Refer to the vendor documentation for specific version numbers. An upgrade is required as there are no known workarounds.

Products

Multiple

Unix

System V

References

Mail List Post: http://securitydigest.org/zardoz/archive/105
http://securitydigest.org/zardoz/archive/106

Manual Testing Notes

Credit

Unknown or Incomplete

CVSSv2 Score

We currently have no CVSS2 data on this vulnerability. Feel free to suggest it.

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