ICE 0xF1

Created the Wednesday 22 June 2022. Updated 6 months, 3 weeks ago.

ICEBP is an undocumented instruction that serves as a single byte interrupt 1, generating a single step exception. It can be used to detect if the program is traced.

Technique Identifier

U0130

Technique Tags

0xf1 icebp

Featured Windows API's

Below, you will find a list of the most commonly used Windows API's that are currently utilized by malware authors for current evasion technique. This list is meant to provide an overview of the API's that are commonly used for this purpose. If there are any API's that you feel should be included on this list, please do not hesitate to contact us. We will be happy to update the list and provide any additional information or documentation that may be helpful.

IsDebuggerPresent

Code Snippets

BOOL IsDebuggerPresent_IceBp()
{
    __try
    { 
        __asm __emit 0xF1 
    }
    __except(1) 
    { 
        return FALSE; 
    }
    return TRUE;
}

Detection Rules

                                    rule Detect_Interrupt: AntiDebug {
    meta: 
        description = "Detect Interrupt instruction"
        author = "Unprotect"
        comment = "Experimental rule / the rule can be slow to use"
    strings:
        $int3 = { CC }
        $intCD = { CD }
        $int03 = { 03 }
        $int2D = { 2D }
        $ICE = { F1 }
    condition:   
       uint16(0) == 0x5A4D and filesize < 1000KB and any of them
}

                                    rule:
  meta:
    name: execute anti-debugging instructions
    namespace: anti-analysis/anti-debugging/debugger-detection
    authors:
      - moritz.raabe@mandiant.com
    scope: function
    mbc:
      - Anti-Behavioral Analysis::Debugger Detection::Anti-debugging Instructions [B0001.034]
    examples:
      - Practical Malware Analysis Lab 16-03.exe_:0x401300
  features:
    - or:
      - count(mnemonic(rdtsc)): 2 or more
      - mnemonic: icebp

Contributors

Thomas Roccia (fr0gger)