CVE-2011-2523

Exp

vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp.

Published: 2019-11-27 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-2523 is rated High Exploit Risk (89.2/100): CVSS Critical severity, with high exploitation likelihood (EPSS 94.26%, 100th percentile). 3 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2011-2523

EDB-ID Source Kind Published Link
49757 exploit_db edb 2021-04-12 Exploit-DB ↗
17491 exploit_db edb 2011-07-05 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2011-2523

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-08-28 94.23% 94.26% +0.03%
2 2025-08-16 94.26% 94.23% -0.03%
3 2025-07-29 — 94.26% —

Full EPSS history (37 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-2523

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
10.0 2.0 HIGH
AV:N/AC:L/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 10.0 [email protected]

Weakness enumeration for CVE-2011-2523

OS Trackers for CVE-2011-2523

vendor priority summary link
debian unimportant CVE-2011-2523 unimportant priority: Debian including 1 source packages (vsftpd), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2011-2523
redhat high — https://access.redhat.com/security/cve/CVE-2011-2523
ubuntu high CVE-2011-2523 high priority: Ubuntu including 1 source packages (vsftpd), 6 status rows across 6 suites (hardy, lucid, maverick, natty, oneiric, upstream): not-affected 5, needs-triage 1. https://ubuntu.com/security/CVE-2011-2523

Affected software / configurations for CVE-2011-2523

Vendor Product Version Raw CPE
vsftpd_project vsftpd 2.3.4 cpe:2.3:a:vsftpd_project:vsftpd:2.3.4:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2011-2523

cvelogic Threat Intelligence