CVE-2018-0202 - Out-of-bounds Read

Severity

43%

Complexity

86%

Confidentiality

48%

clamscan in ClamAV before 0.99.4 contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper input validation checking mechanisms when handling Portable Document Format (.pdf) files sent to an affected device. An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted .pdf file to an affected device. This action could cause an out-of-bounds read when ClamAV scans the malicious file, allowing the attacker to cause a DoS condition. This concerns pdf_parse_array and pdf_parse_string in libclamav/pdfng.c. Cisco Bug IDs: CSCvh91380, CSCvh91400.

clamscan in ClamAV before 0.99.4 contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper input validation checking mechanisms when handling Portable Document Format (.pdf) files sent to an affected device. An unauthenticated, remote attacker could exploit this vulnerability by sending a crafted .pdf file to an affected device. This action could cause an out-of-bounds read when ClamAV scans the malicious file, allowing the attacker to cause a DoS condition. This concerns pdf_parse_array and pdf_parse_string in libclamav/pdfng.c. Cisco Bug IDs: CSCvh91380, CSCvh91400.

CVSS 3.0 Base Score 5.5. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H).

CVSS 2.0 Base Score 4.3. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:N/I:N/A:P).

Demo Examples

Out-of-bounds Read

CWE-125

In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method


               
}
return value;// check that the array index is less than the maximum// length of the array
value = array[index];// get the value at the specified index of the array
// if array index is invalid then output error message// and return value indicating error
value = -1;

However, this method only verifies that the given array index is less than the maximum length of the array but does not check for the minimum value (CWE-839). This will allow a negative value to be accepted as the input array index, which will result in a out of bounds read (CWE-125) and may allow access to sensitive memory. The input array index should be checked to verify that is within the maximum and minimum range required for the array (CWE-129). In this example the if statement should be modified to include a minimum range check, as shown below.


               
...// check that the array index is within the correct// range of values for the array

Overview

First reported 6 years ago

2018-03-27 09:29:00

Last updated 5 years ago

2019-03-26 16:02:00

Affected Software

ClamAV

Canonical Ubuntu Linux 12.04 ESM (Extended Security Maintenance)

12.04

Canonical Ubuntu Linux 14.04 LTS (Long-Term Support)

14.04

Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)

16.04

Canonical Ubuntu Linux 17.10

17.10

Debian Linux 7.0

7.0

Stay updated

ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.

Get in touch

If you'd like to report a bug or have any suggestions for improvements then please do get in touch with us using this form. We will get back to you as soon as we can.