Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cf4b31fd2d91d68…

MALICIOUS

PDF

77.0 KB Created: 2021-09-17 15:56:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: e3daa40de727d4b0599630b58c7b417d SHA-1: 79ad88a28863c51db5da9dd486eb077170b510ea SHA-256: 4cf4b31fd2d91d68e126788752fa7d1e8c7fe083d47ec2a3b6f3a4d18a6f592e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was identified as malicious by a machine learning classifier and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple compromised or disposable hosting sites, likely for phishing or malware distribution. The presence of numerous unknown URLs suggests a broad attempt to redirect victims.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613686ba84be0---nosirobakuzetilijufoxoze.pdf In PDF document text
    • http://kgmda.com/upload/files/2700667370.pdfIn PDF document text
    • http://amdind.com/userfiles/file/19570636236.pdfIn PDF document text
    • https://pemaboutiquehotel.com/assets/userfiles/files/2629874594.pdfIn PDF document text
    • http://ambvetsanprospero.eu/userfiles/files/fetijuvilimo.pdfIn PDF document text
    • http://xedaphcm.com/luutru/files/giteme.pdfIn PDF document text
    • https://inwestorfinanse.pl/userfiles/file/23626913063.pdfIn PDF document text
    • http://kdsonline.org/userfiles/file/3350674659.pdfIn PDF document text
    • http://tentimesneedlehill.com/UPFILE/userfiles/files/18908241854.pdfIn PDF document text
    • http://autothudo.vn/upload/fck/file/tugibobaralexusujad.pdfIn PDF document text
    • http://klenderbio.com/upload/files/87310318925.pdfIn PDF document text
    • https://zooiguana.pl/app/webroot/media/files/janidub.pdfIn PDF document text
    • http://jnmindia.com/outscapes/admin/ckeditor/uploads/ck/files/42916764028.pdfIn PDF document text
    • https://sudhirsachdevaclasses.com/ci/userfiles/files/sakagawelinew.pdfIn PDF document text
    • http://aleeblog.com/wp-content/plugins/super-forms/uploads/php/files/gpp9oh5e0nlbjrtrkh8rvks6f5/98494834316.pdfIn PDF document text
    • https://www.hadlowsecurityshutters.com/wp-content/plugins/super-forms/uploads/php/files/4c5c95b9c3c890a352a1ee5b45f45b1f/93518656852.pdfIn PDF document text
    • http://fabrykakonwersji.pl/wp-content/plugins/super-forms/uploads/php/files/ed766783fcc08d7ca61e97f3bb7f25c9/9978500995.pdfIn PDF document text
    • https://marikakozmetika.hu/editor_up/89092947117.pdfIn PDF document text
    • https://creativenursery.net/home/creative/public_html/ckfinder/userfiles/files/46739538078.pdfIn PDF document text
    • https://valkexclusief.reviewz.eu/app/webroot/files/userfiles/files/21652440113.pdfIn PDF document text
    • http://ivankotov.ru/img/lib/file/sumipakifipuxipeb.pdfIn PDF document text
    • http://khonggianxua.samdigroup.vn/app/webroot/upload/files/97681843264.pdfIn PDF document text
    • http://jfhcoaching.com/userfiles/files/72730187493.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=free+streaming+soccer+tvPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c7eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7EB 10568 bytes
SHA-256: 3bae502458194519faa05a3efdbc955126be02a21293e9af80ceb81e6bfe2c46
font_01_sfnt_off0000e016.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE016 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f828.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF828 18184 bytes
SHA-256: fbaf51c8985cd16b0e7d5bc051e8b03414f5377638c397346fbd43cc61ac65cb