procps: process hiding through race condition enumerating /proc
Published Jun 13, 2018
5.9
MEDIUMCVSS 3.0
EPSS 4.19%
Description
procps-ng, procps is vulnerable to a process hiding through race condition. Since the kernel's proc_pid_readdir() returns PID entries in ascending numeric order, a process occupying a high PID can use inotify events to determine when the process list is being scanned, and fork/exec to obtain a lower PID, thus avoiding enumeration. An unprivileged attacker can hide a process from procps-ng's utilities by exploiting a race condition in reading /proc/PID entries. This vulnerability affects procps and procps-ng up to version 3.3.15, newer versions might be affected also.
Affected products
- Vendor n/a Product Procps-Ng, Procps Defaultn/a
- Version up to procps-ng 3.3.15 and newerStatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n/a | Procps-Ng, Procps | n/a |
|
- ≤ 3.3.15
No data.
Red Hat Enterprise Linux 5
procps
Will not fix
Red Hat Enterprise Linux 6
procps
Will not fix
Red Hat Enterprise Linux 7
procps-ng
Will not fix
Red Hat Enterprise Linux 8
procps-ng
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 5 | procps | Will not fix | n/a |
| Red Hat Enterprise Linux 6 | procps | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | procps-ng | Will not fix | n/a |
| Red Hat Enterprise Linux 8 | procps-ng | Will not fix | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
The /proc filesystem is not a reliable mechanism to account for processes running on a system, as it is unable to offer snapshot semantics. Short-lived processes have always been able to escape detection by tools that monitor /proc. This CVE simply identifies a reliable way to do so using inotify. Process accounting for security purposes, or with a requirement to record very short-running processes and those attempting to evade detection, should be performed with more robust methods such as auditd(8) (the Linux Audit Daemon) or systemtap. Because an attacker can achieve similar results whether this vulnerability is present or not, Red Hat assesses its impact as Low.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
1 other source (Red Hat) ▾
CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
AV:N/AC:M/Au:N/C:N/I:P/A:N
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (19 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.19% (0.04189) | 90.62th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.19% (0.04189) | 89.61th | v5 (v2026.06.15) |
| Mar 30, 2025 | 2.08% (0.02080) | 82.41th | v4 (v2025.03.14) |
| Mar 29, 2025 | 5.35% (0.05353) | 83.09th | v4 (v2025.03.14) |
| Mar 17, 2025 | 2.12% (0.02120) | 82.96th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.18% (0.00178) | 56.20th | v3 (v2023.03.01) |
| Nov 4, 2023 | 0.18% (0.00178) | 54.81th | v3 (v2023.03.01) |
| Jul 8, 2023 | 0.21% (0.00210) | 57.86th | v3 (v2023.03.01) |
| Jun 7, 2023 | 0.36% (0.00359) | 68.13th | v3 (v2023.03.01) |
| May 8, 2023 | 0.42% (0.00417) | 70.23th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.24% (0.00244) | 60.49th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.02% (0.01018) | 40.69th | v2 (v2022.01.01) |
| Sep 10, 2022 | 1.02% (0.01018) | 38.88th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.02% (0.01018) | 36.86th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.02% (0.01018) | 19.50th | v2 (v2022.01.01) |
| Feb 3, 2022 | 5.36% (0.05363) | 79.74th | v1 |
| Jan 6, 2022 | 5.36% (0.05363) | 79.54th | v1 |
| Sep 1, 2021 | 5.36% (0.05363) | 88.35th | v1 |
| Apr 14, 2021 | 5.36% (0.05363) | 0.00th | v1 |
References (9)
- http://seclists.org/oss-sec/2018/q2/122 mailing-listx_refsource_MLISTExploitMailing ListThird Party Advisory
- http://www.securityfocus.com/bid/104214 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://access.redhat.com/security/cve/CVE-2018-1121 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1575473 Issue Tracking
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1121 x_refsource_CONFIRMIssue TrackingThird Party Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2018-1121
- https://www.cve.org/CVERecord?id=CVE-2018-1121
- https://www.exploit-db.com/exploits/44806/ exploitx_refsource_EXPLOIT-DBThird Party AdvisoryVDB Entry
- https://www.qualys.com/2018/05/17/procps-ng-audit-report-advisory.txt x_refsource_MISCExploitThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| http://seclists.org/oss-sec/2018/q2/122 | mailing-listx_refsource_MLISTExploitMailing ListThird Party Advisory | |
| http://www.securityfocus.com/bid/104214 | vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry | |
| https://access.redhat.com/security/cve/CVE-2018-1121 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1575473 | Issue Tracking | |
| https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1121 | x_refsource_CONFIRMIssue TrackingThird Party Advisory | |
| https://nvd.nist.gov/vuln/detail/CVE-2018-1121 | ||
| https://www.cve.org/CVERecord?id=CVE-2018-1121 | ||
| https://www.exploit-db.com/exploits/44806/ | exploitx_refsource_EXPLOIT-DBThird Party AdvisoryVDB Entry | |
| https://www.qualys.com/2018/05/17/procps-ng-audit-report-advisory.txt | x_refsource_MISCExploitThird Party Advisory |
Change history (0)
No recorded changes yet.