CVE-2015-3156
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe _write_config function in trove/guestagent/datastore/experimental/mongodb/service.py, reset_configuration function in trove/guestagent/datastore/experimental/postgresql/service/config.py, write_config function in trove/guestagent/datastore/experimental/redis/service.py, _write_mycnf function in trove/guestagent/datastore/mysql/service.py, InnoBackupEx::_run_prepare function in trove/guestagent/strategies/restore/mysql_impl.py, InnoBackupEx::cmd function in trove/guestagent/strategies/backup/mysql_impl.py, MySQLDump::cmd in trove/guestagent/strategies/backup/mysql_impl.py, InnoBackupExIncremental::cmd function in trove/guestagent/strategies/backup/mysql_impl.py, _get_actual_db_status function in trove/guestagent/datastore/experimental/cassandra/system.py and trove/guestagent/datastore/experimental/cassandra/service.py, and multiple class CbBackup methods in trove/guestagent/strategies/backup/experimental/couchbase_impl.py in Openstack DBaaS (aka Trove) as packaged in Openstack before 2015.1.0 (aka Kilo) allows local users to write to configuration files via a symlink attack on a temporary file.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceOpenStack Trove guest agent contains multiple functions (_write_config, reset_configuration, write_config, _write_mycnf, etc.) that create temporary configuration files unsafely. These functions are vulnerable to symlink attacks where a local user can replace the temporary file with a symlink before the write operation completes, allowing arbitrary file write as root privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2014.2.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Locate Trove guest agent installationSearch for trove-guestagent package or files: run 'pip list | grep -i trove', 'find /usr -name "*trove*guest*" 2>/dev/null', or check /opt for trove directoriesAffected if No Trove guest agent is found, then the system is not affected by this CVE
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Determine installed versionRun 'pip show trove-guestagent' or check the version file in the installation directory, then compare the version number to 2014.2.4Affected if The installed version is 2014.2.4 or earlier (e.g., 2014.2.3, 2014.2.2, etc.)
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Find vulnerable functions in source codeLocate the guest agent source code (typically in site-packages/trove_guestagent/ or similar), then search for function definitions: grep -r '_write_config\|reset_configuration\|write_config\|_write_mycnf' in the guest agent directoryAffected if These functions exist in the codebase, indicating the vulnerable code is present
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Inspect temporary file creation patternsWithin the identified functions, examine how temporary files are created. Look for patterns like mktemp(), open(tempfile, 'w'), or direct writes to /tmp without secure handling. Search for patterns such as: grep -A 20 'def _write_config' <source_file>Affected if The code uses insecure methods to create temporary configuration files (e.g., predictable filenames in /tmp, lack of atomic operations, or missing file permissions checks)
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Verify symlink vulnerability existsCheck if the temp file operations lack proper safeguards. Look for: 1) absence of os.rename() for atomic moves, 2) no use of tempfile.NamedTemporaryFile with delete=False, 3) no umask or chmod restrictions before writing, 4) no checking if the target is already a symlinkAffected if The code performs direct writes to temporary files without atomic move operations or symlink checks, making it exploitable
A system is affected if OpenStack Trove guest agent version 2014.2.4 or earlier is installed and contains the vulnerable temporary file functions with insecure creation patterns.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataReplace unsafe temporary file operations with secure practices: use tempfile.NamedTemporaryFile with delete=False and appropriate permissions, or write to a secure temporary directory with restricted permissions, then atomically move the file to its final destination.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2015-3156 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-3156 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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