Vulnerability Name:

CVE-2020-12883 (CCN-183641)

Assigned:2020-05-12
Published:2020-05-12
Updated:2021-07-21
Summary:Buffer over-reads were discovered in the CoAP library in Arm Mbed OS 5.15.3. The CoAP parser is responsible for parsing received CoAP packets. The function sn_coap_parser_options_parse() parses CoAP input linearly using a while loop. Once an option is parsed in a loop, the current point (*packet_data_pptr) is increased correspondingly. The pointer is restricted by the size of the received buffer, as well as by the option delta and option length bytes. The actual input packet length is not verified against the number of bytes read when processing the option extended delta and the option extended length. Moreover, the calculation of the message_left variable, in the case of non-extended option deltas, is incorrect and indicates more data left for processing than provided in the function input. All of these lead to heap-based or stack-based memory location read access that is outside of the intended boundary of the buffer. Depending on the platform-specific memory management mechanisms, it can lead to processing of unintended inputs or system memory access violation errors.
CVSS v3 Severity:9.1 Critical (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H)
7.9 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): None
Availibility (A): High
5.3 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
4.6 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Low
CVSS v2 Severity:6.4 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): Partial
5.0 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
Vulnerability Type:CWE-119
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2020-12883

Source: XF
Type: UNKNOWN
armmbed-cve202012883-dos(183641)

Source: CONFIRM
Type: Third Party Advisory
https://github.com/ARMmbed/mbed-coap/pull/116

Source: MISC
Type: Third Party Advisory
https://github.com/ARMmbed/mbed-os/issues/12925

Source: CCN
Type: Mbed OS GIT Repository
Out of range memory access in MbedOS CoAP library parser - option number #12926

Source: MISC
Type: Third Party Advisory
https://github.com/ARMmbed/mbed-os/issues/12926

Source: MISC
Type: Third Party Advisory
https://github.com/ARMmbed/mbed-os/issues/12927

Vulnerable Configuration:Configuration 1:
  • cpe:/o:arm:mbed_os:5.15.3:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    arm mbed os 5.15.3