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cve[email protected]CVE-2017-1000254
HistoryOct 06, 2017 - 1:29 p.m.

CVE-2017-1000254

2017-10-0613:29:00
CWE-119
web.nvd.nist.gov
156
2
cve-2017-1000254
libcurl
ftp
directory name parsing
buffer overflow
security vulnerability
nvd

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

7.4 High

AI Score

Confidence

High

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.009 Low

EPSS

Percentile

82.3%

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

Social References

More

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

7.4 High

AI Score

Confidence

High

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.009 Low

EPSS

Percentile

82.3%

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