Malicious PDF — malware analysis report

Static analysis result for SHA-256 efccbf7472065575…

MALICIOUS

PDF

19.4 KB
MD5: f3436bd7376d0e1bf576cae549429829 SHA-1: 5ecc0e62c6fa28b013511136ff06a9e6885af718 SHA-256: efccbf7472065575d3cb28b41fa727271ffa55c0c1ad3c38050a6ec7d39ebad7
104 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF sample contains a high-confidence heuristic firing for 'XFA form contains risky executable script'. This indicates that the embedded XFA script is malicious. The script is likely designed to download and execute a second-stage payload, as suggested by the 'PDF_EMBEDDED' and 'EXTRACTED_FILE_STATIC_TRIAGE' heuristics which point to suspicious embedded files and script obfuscation. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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.
  • 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
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.xfa.org/schema/xfa-locale-set/2.1/

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0041.bin
c06dcd026a7ea0536b63e07ce688691b585339a3ab7ff59065e546b56308c7bb
pdf-embedded-file PDF EmbeddedFile object 41 at offset 0x3AB3 85 bytes
embedded_file_obj0042.bin
dda0835df994b8be920f715db36452f6cee7bb42bbc9c897f878a7b298ba8e91
pdf-embedded-file PDF EmbeddedFile object 42 at offset 0x3B65 1029 bytes
embedded_file_obj0043.bin
1398c66c3ca1bf56ef9b2337f1d295022afef840659b8821c521c025c37b9ded
pdf-embedded-file PDF EmbeddedFile object 43 at offset 0x3D7E 1598 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
embedded_file_obj0044.bin
3dd68f00f4fcb366a2a3a17c65cb2626eeddf5ea5713302d374310561d810169
pdf-embedded-file PDF EmbeddedFile object 44 at offset 0x410F 144 bytes
embedded_file_obj0045.bin
10c03f88a5f0a0833dc5b2c8ac295b3a3c6f65e23889eb8cc1dc6fe29bf7f275
pdf-embedded-file PDF EmbeddedFile object 45 at offset 0x41BB 77 bytes
font_00_cff_off000042cf.bin
062eede2d0cc5d3972869dc7e2f2f9f01d1d1b3756b715c8252f06948ce99ae2
pdf-font-stream PDF embedded font (cff) at offset 0x42CF 1192 bytes