Debian update for tor
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 3 |
| CVE-ID | CVE-2021-34548 CVE-2021-34549 CVE-2021-34550 |
| CWE-ID | CWE-200 CWE-399 CWE-125 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
tor (Debian package) Operating systems & Components / Operating system package or component |
| Vendor | Debian |
Security Bulletin
This security bulletin contains information about 3 vulnerabilities.
1) Information disclosure
EUVDB-ID: #VU54229
Risk: Medium
CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34548
CWE-ID:
CWE-200 - Information exposure
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform spoofing attack.
The vulnerability exists due to incorrect processing of user-supplied data. A remote attacker can spoof RELAY_END or RELAY_RESOLVED cell on half-closed streams, which would allow a relay on a circuit to end a stream that wasn't actually built with it.
MitigationUpdate tor package to version 0.3.5.15-1.
Vulnerable software versionstor (Debian package): 0.3.5.3-alpha-1 - 0.3.5.14-1
External linkshttp://www.debian.org/security/2021/dsa-4932
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Resource management error
EUVDB-ID: #VU54230
Risk: Low
CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34549
CWE-ID:
CWE-399 - Resource Management Errors
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper management of internal resources within the naive unkeyed hash function. A remote attacker can construct circuits with chosen circuit IDs, to create collisions and make the hash table inefficient, resulting in denial of service condition.
Update tor package to version 0.3.5.15-1.
Vulnerable software versionstor (Debian package): 0.3.5.3-alpha-1 - 0.3.5.14-1
External linkshttp://www.debian.org/security/2021/dsa-4932
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
3) Out-of-bounds read
EUVDB-ID: #VU54231
Risk: Low
CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34550
CWE-ID:
CWE-125 - Out-of-bounds read
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition during v3 onion service descriptor parsing. A remote attacker can create an onion service descriptor that would crash any client that tried to visit it.
MitigationUpdate tor package to version 0.3.5.15-1.
Vulnerable software versionstor (Debian package): 0.3.5.3-alpha-1 - 0.3.5.14-1
External linkshttp://www.debian.org/security/2021/dsa-4932
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
