Exim 4.88/4.89 SMTP Daemon receive.c bdat_getc resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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6.1$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in Exim 4.88/4.89. This affects the function bdat_getc of the file receive.c of the component SMTP Daemon. This manipulation causes resource consumption. The identification of this vulnerability is CVE-2017-16944. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Exim 4.88/4.89 (Mail Server Software). It has been declared as problematic. Affected by this vulnerability is the function bdat_getc of the file receive.c of the component SMTP Daemon. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to cause a denial of service (infinite loop and stack exhaustion) via vectors involving BDAT commands and an improper check for a '.' character signifying the end of the content, related to the bdat_getc function.

The bug was discovered 11/26/2017. The weakness was shared 11/25/2017 by meh as EDB-ID 43184 as confirmed exploit (Exploit-DB). The advisory is shared at exploit-db.com. This vulnerability is known as CVE-2017-16944 since 11/25/2017. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known. MITRE ATT&CK project uses the attack technique T1499 for this issue.

A public exploit has been developed by meh and been published 2 days after the advisory. It is possible to download the exploit at exploit-db.com. It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 104882 (Ubuntu 17.04 / 17.10 : exim4 vulnerability (USN-3499-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 176233 (Debian Security Update for exim4 (DSA 4053-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 4 days after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (43184), Tenable (104882) and SecurityTracker (ID 1039873†). The entry VDB-109968 is related to this item. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: meh
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 104882
Nessus Name: Ubuntu 17.04 / 17.10 : exim4 vulnerability (USN-3499-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 862331
OpenVAS Name: Ubuntu Update for exim4 USN-3499-1
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Timelineinfo

11/25/2017 🔍
11/25/2017 +0 days 🔍
11/25/2017 +0 days 🔍
11/26/2017 +1 days 🔍
11/26/2017 +0 days 🔍
11/27/2017 +1 days 🔍
11/27/2017 +0 days 🔍
11/27/2017 +0 days 🔍
11/29/2017 +2 days 🔍
11/30/2017 +1 days 🔍
03/26/2025 +2673 days 🔍

Sourcesinfo

Advisory: EDB-ID 43184
Researcher: meh
Status: Confirmed

CVE: CVE-2017-16944 (🔍)
GCVE (CVE): GCVE-0-2017-16944
GCVE (VulDB): GCVE-100-109969

OVAL: 🔍

SecurityTracker: 1039873

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 11/26/2017 16:41
Updated: 03/26/2025 03:22
Changes: 11/26/2017 16:41 (86), 12/11/2019 20:47 (6), 03/26/2025 03:22 (17)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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