Malicious PDF — malware analysis report

Static analysis result for SHA-256 33bac691de513c8c…

MALICIOUS

PDF

5.1 KB
MD5: 383a73c0f2c489811ed1b09bd3477710 SHA-1: e2185169a3f48dfd8a89f5a4a781b82c50f24a8b SHA-256: 33bac691de513c8c86b7b2d2927563d68a3e21411560b86563050669ca34e265
170 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: Malicious File

The PDF contains XFA form elements that trigger a heap spray vulnerability, leading to the execution of embedded JavaScript. This script is designed to download and execute a secondary payload, as indicated by the 'PDF_XFA_HEAP_SPRAY' and 'PDF_XFA_SCRIPT' heuristic firings. The ML classifier strongly supports the malicious nature of this PDF. No specific family could be identified, but the attack pattern is consistent with PDF-based exploit delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT
    PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
  • XFA JavaScript heap-spray exploit code critical PDF_XFA_HEAP_SPRAY
    PDF contains XFA script content with heap-spray or shellcode-like JavaScript markers such as large encoded word sequences, util.pack, large arrays, or spray variable names. This is a weaponised Adobe Reader exploit pattern, not a normal interactive form.
  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin
ad7f6ed5c376a24525f70c8ae23e8f62b41fbb56252bd77fa35f35a3ef2c836a
pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xA50 4881 bytes