Rule Category

INDICATOR-COMPROMISE -- Snort detected a system behavior that suggests the system has been affected by malware. That behavior is known as an Indicator of Compromise (IOC). The symptoms could be a wide range of behaviors, from a suspicious file name to an unusual use of a utility. Symptoms do not guarantee an infection; your network configuration may not be affected by malware, but showing indicators as a result of a normal function. In this case, attackers may be attempting to gain privileges and access other systems, spread influence, and make calls and commands with elevated access. The context of the traffic is important to determine intrusion; traffic from an administration utility performing commands on a user's computer is likely not a compromise, but a user laptop accessing a webserver may indicate intrusion.

Alert Message

INDICATOR-COMPROMISE Microsoft Windows Interrupt Service Routine stack rollback attempt

Rule Explanation

This event is generated when shellcode is detected that attempts to "rollback" the Interrupt Service Routine (ISR). Impact: Attempted User Privilege Gain Details: Ease of Attack:

What To Look For

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic:

Technique:

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

CVE

CVE Additional Information

CVE-2018-8897
A statement in the System Programming Guide of the Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) was mishandled in the development of some or all operating-system kernels, resulting in unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS, as demonstrated by (for example) privilege escalation in Windows, macOS, some Xen configurations, or FreeBSD, or a Linux kernel crash. The MOV to SS and POP SS instructions inhibit interrupts (including NMIs), data breakpoints, and single step trap exceptions until the instruction boundary following the next instruction (SDM Vol. 3A; section 6.8.3). (The inhibited data breakpoints are those on memory accessed by the MOV to SS or POP to SS instruction itself.) Note that debug exceptions are not inhibited by the interrupt enable (EFLAGS.IF) system flag (SDM Vol. 3A; section 2.3). If the instruction following the MOV to SS or POP to SS instruction is an instruction like SYSCALL, SYSENTER, INT 3, etc. that transfers control to the operating system at CPL < 3, the debug exception is delivered after the transfer to CPL < 3 is complete. OS kernels may not expect this order of events and may therefore experience unexpected behavior when it occurs.
Details
Severity Base Score7.8
Impact Score5.9 Exploit Score1.8
Confidentiality ImpactHIGH Integrity ImpactHIGH
Availability ImpactHIGH Access Vector
Authentication Ease of Access