Category Archives: Advisories

Kernel Level Rat “Daxin” Discovered

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FortiGuard Labs is aware of a newly discovered backdoor dubbed Daxin. Discovered by Symantec, this backdoor allows an attacker to gather and perform various command and control actions and data exfiltration on victim machines. Because of our partnership with the Cyber Threat Alliance, we were provided with IOCs to create Fortinet protections in advance so that it would be ready for today’s announcement.What separates this backdoor from many others is that Daxin is a Windows kernel level driver, also referred to as rootkits. Kernel level rootkits operate at ring 0, which allows them to operate at
the highest privileges of the operating system with impunity. What makes this threat dangerous and very effective is that it is able to leverage existing services and utilize them to perform whatever is needed without raising any suspicion by network administrators and or endpoint security software. Daxin does not contain any unique capabilities from other backdoors; however, besides its ability to run at kernel level, Daxin can also intercept TCP/IP connections in real time for further evasion. Further communications noted were the use of a custom TCP/IP stack to communicate in multiple nodes on highly secured networks.This backdoor has been attributed to state sponsored threat actors of China where targets are organizations that are of interest to the Chinese government.What Operating Systems Were Targeted?Windows operating systems.What is the Likelihood of Exploitation?Low. This is due to the attacks observed being focused on the specific interests by the threat actors behind Daxin, and not as part of a widespread attack.Is this Limited to Targeted Attacks?Yes, all attacks observed were limited to state sponsored targets. This included governmental organizations of interest, telecommunications, transportation, and manufacturing sectors as well.What is the Status of Coverage?Customers running the latest AV definitions are protected by the following signatures:W32/Agent.FF56!tr.bdrW32/Backdoor.DAXIN!trW32/PossibleThreatW64/Agent.FF56!tr.bdrW64/Backdoor.DAXIN!trW64/Agent.QWHWSZ!trMalicious_Behavior.SBW32/Exforel.B!tr.bdrDx.BG3D!trW64/Agent.WT!trW32/PossibleThreat

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USN-5310-1: GNU C Library vulnerabilities

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Jan Engelhardt, Tavis Ormandy, and others discovered that the GNU C Library
iconv feature incorrectly handled certain input sequences. An attacker
could possibly use this issue to cause the GNU C Library to hang or crash,
resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS
and Ubuntu 20.04 LTS. (CVE-2016-10228, CVE-2019-25013, CVE-2020-27618,
CVE-2020-29562, CVE-2021-3326)

Jason Royes and Samuel Dytrych discovered that the GNU C Library
incorrectly handled signed comparisons on ARMv7 targets. A remote attacker
could use this issue to cause the GNU C Library to crash, resulting in a
denial of service, or possibly execute arbitrary code. This issue only
affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-6096)

It was discovered that the GNU C Library nscd daemon incorrectly handled
certain netgroup lookups. An attacker could possibly use this issue to
cause the GNU C Library to crash, resulting in a denial of service. This
issue only affected Ubuntu 20.04 LTS. (CVE-2021-27645)

It was discovered that the GNU C Library wordexp function incorrectly
handled certain patterns. An attacker could use this issue to cause the
GNU C Library to crash, resulting in a denial of service, or possibly
obtain sensitive information. This issue only affected Ubuntu 18.04 LTS and
Ubuntu 20.04 LTS. (CVE-2021-35942)

It was discovered that the GNU C Library realpath function incorrectly
handled return values. An attacker could possibly use this issue to obtain
sensitive information. This issue only affected Ubuntu 21.10.
(CVE-2021-3998)

It was discovered that the GNU C library getcwd function incorrectly
handled buffers. An attacker could use this issue to cause the GNU C
Library to crash, resulting in a denial of service, or possibly execute
arbitrary code. (CVE-2021-3999)

It was discovered that the GNU C Library sunrpc module incorrectly handled
buffer lengths. An attacker could possibly use this issue to cause the GNU
C Library to crash, resulting in a denial of service. (CVE-2022-23218,
CVE-2022-23219)

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