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Medium severity · published Jun 6, 2021
CVE-2021-33881
On NXP MIFARE Ultralight and NTAG cards, an attacker can interrupt a write operation (aka conduct a "tear off" attack) over RFID to bypass a Monotonic Counter protection mechanism
4.2
CVSS
0.4%
EPSS
No
On KEV
Description
On NXP MIFARE Ultralight and NTAG cards, an attacker can interrupt a write operation (aka conduct a "tear off" attack) over RFID to bypass a Monotonic Counter protection mechanism. The impact depends on how the anti tear-off feature is used in specific applications such as public transportation, physical access control, etc.
CVSS vector
CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Physical
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 35% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MU
Mifare Ultralight C Firmware · Nxp
All versions, or not specified · source: NVD
MU
Mifare Ultralight Ev1 Firmware · Nxp
All versions, or not specified · source: NVD
MU
Mifare Ultralight Nano Firmware · Nxp
All versions, or not specified · source: NVD
N2
Ntag 210 Firmware · Nxp
All versions, or not specified · source: NVD
N2
Ntag 212 Firmware · Nxp
All versions, or not specified · source: NVD
N2
Ntag 213 Firmware · Nxp
All versions, or not specified · source: NVD
N2
Ntag 215 Firmware · Nxp
All versions, or not specified · source: NVD
N2
Ntag 216 Firmware · Nxp
All versions, or not specified · source: NVD
Affected product
MU
Mifare Ultralight C Firmware
Nxp
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-33881
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-33881
Mitigation
https://blog.quarkslab.com/rfid-monotonic-counter-anti-tearing-defeated.html
Vendor Advisory
https://www.nxp.com/docs/en/application-note/AN11340.pdf
Vendor Advisory
https://www.nxp.com/docs/en/application-note/AN13089.pdf
Exploit
https://www.sstic.org/2021/presentation/eeprom_it_will_all_end_in_tears/