Apache Struts Deserialization of Untrusted Data
CVE-2017-9805 is a high-severity deserialization of untrusted data vulnerability in Apache Struts from Apache, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Struts versions: Apache Struts before 2.3.34 and 2.5.x before 2.5.13. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Struts to 2.3.34 or 2.5.13, whichever matches your release line, or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on oracle.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Struts | Apache Struts before 2.3.34 and 2.5.x before 2.5.13 | Not stated |
| Apache | Struts | 2.1.2 up to, but not including, 2.3.34; 2.5.0 up to, but not including, 2.5.13 | 2.3.34, 2.5.13 |
| Cisco | Digital Media Manager | Not specified in the record | Not stated |
| Cisco | Hosted Collaboration Solution | 10.5\(1\); 11.0\(1\); 11.5\(1\); 11.6\(1\) | Not stated |
| Cisco | Media Experience Engine | 3.5; 3.5.2 | Not stated |
| Cisco | Network Performance Analysis | Not specified in the record | Not stated |
| Cisco | Video Distribution Suite For Internet Streaming | Not specified in the record | Not stated |
| NetApp | Oncommand Balance | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.1 | High | NVD |
| CVSS 3.1 | 8.1 | High | CISA (ADP) |
| CVSS 2.0 | 6.8 | Medium | NVD |
Official description
The REST Plugin in Apache Struts 2.1.1 through 2.3.x before 2.3.34 and 2.5.x before 2.5.13 uses an XStreamHandler with an instance of XStream for deserialization without any type filtering, which can lead to Remote Code Execution when deserializing XML payloads.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- bugzilla.redhat.com/show_bug.cgi?id=1488482Issue Tracking, Third Party Advisory, VDB Entry
- security.netapp.com/advisory/ntap-20170907-0001/Third Party Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170907-struts2Third Party Advisory
- kb.cert.org/vuls/id/112992Third Party Advisory, US Government Resource
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-9805US Government Resource
Technical write-ups (may include proof of concept)
- exploit-db.com/exploits/42627/Exploit, Third Party Advisory, VDB Entry
Other vulnerabilities in Apache Struts
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.8 Critical severity
Adobe ColdFusion Deserialization Exploited
- 9.8 Critical severity
- 9.8 Critical severity
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