Malicious PDF — malware analysis report

Static analysis result for SHA-256 d9ffd85c6736e9d0…

MALICIOUS

PDF

79.3 KB Created: 2021-04-27 15:28:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-31
MD5: 8fbed106e3d5f18da4416a4f2d9124f0 SHA-1: e7a1f5f7bb45a0fe5aec8047306a32804e108266 SHA-256: d9ffd85c6736e9d0e98c5dc79ede6c7dc6083a1f9f56b6e7640bcf42acdb1341
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded links, many pointing to unknown or potentially malicious domains, suggesting an attempt to redirect users to phishing or malware hosting sites. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, which is sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.
  • 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.grotekeukens.be/sites/default/files/webform/gmawards2018/sumeli.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/tefofavokalozigukar.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/fulakosilukubusovugatupus.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/mikax.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/jilagofuzepev.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/talazeleravu.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/26688185713.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=can+you+have+piercings+working+at+starbucksPDF link annotation
    • https://minorsoncampus.princeton.edu/system/files/webform/45540448673.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/86005813007.pdfIn PDF document text
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/wutiladerotegedubel.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/vijebutipide.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/buviboxakutovovujigobimis.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/zupedofijemurak.pdfIn PDF document text
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/60395266702.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF57 2900 bytes
SHA-256: b3dfb2f2c41da7350fc3755141d2fd0ea5796bb125df25fec831093623ff73df
font_01_sfnt_off0000f99a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF99A 5524 bytes
SHA-256: 39b2a31248a6849c70348e9b13339bad0b844f284445d69550b49154b03e6cd7
font_02_sfnt_off00010c79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C79 10604 bytes
SHA-256: bcf34ac643d08a82017cc27687192e0318ada65719c7208f76b119e9e9194b04