Malicious PDF — malware analysis report

Static analysis result for SHA-256 5837dfa4733df2a5…

MALICIOUS

PDF

86.8 KB Created: 2021-08-11 15:16:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 7f64bfd95e33c9334bc5ff6812b8b8b6 SHA-1: 83d5dba6c108a747b929eb52e35802f0ec20427f SHA-256: 5837dfa4733df2a53a04263c9b6f174fd7b96fe05d0fd9d19ef6c5cb428cf9ef
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of these links and the PDF's structure strongly indicate a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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 https://laborke.ru/uplcv?utm_term=definisi+karya+tulis+ilmiah+pdf PDF link annotation
    • http://ytbozhuo.com/upload/file/230148108898.pdfIn PDF document text
    • http://xn----8sbaqfskngn1qi.xn--p1ai/userfiles/file/valafemuxi.pdfIn PDF document text
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c18c651e00f---28051833584.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd7aabb3c17---zikabevazenise.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/60919156793.pdfIn PDF document text
    • http://stlnsk.ru/uploads/file/fesezikexip.pdfIn PDF document text
    • https://multimetrics.com/ckfinder/userfiles/files/suvujalexawo.pdfIn PDF document text
    • http://erpsamik.com/ckfinder/userfiles/files/jefadanunojirikesutoguze.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160fccd48656d1---7490248100.pdfIn PDF document text
    • https://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/5308accd3b85b0ebf6d14e6cff9c782c/berolo.pdfIn PDF document text
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/c5cac3b191ce8afeddf70124f603a923/gurekavobunawisenipo.pdfIn PDF document text
    • https://ibeguiristain.com/userfiles/files/bulelugoxidonemedewes.pdfIn PDF document text
    • http://ccspatti.org/userfiles/file/82583637911.pdfIn PDF document text
    • http://about-dogs.ru/upload/file/wigip.pdfIn PDF document text
    • https://fietenhaardenenkachels.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160bf65a6674f6---23754180394.pdfIn PDF document text
    • http://photographybynami.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be93bd9f5d3---siwifaku.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c27049f0faf---52861780857.pdfIn PDF document text
    • https://burragebrothers.com/demo/jolie/beta/userfiles/files/bitozutarupururotexagi.pdfIn PDF document text
    • https://majubesar.org/contents//files/36972224317.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/7el38p0fbvtes17e7fn3ldrjv1/savovizavomalapexojiko.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://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_off0000f00c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF00C 16628 bytes
SHA-256: cc4e776e93645ea06cfff0d4c1275290d6c7a7f61b9ca701c9ae1e7ff676b456
font_01_sfnt_off00011b6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B6C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013383.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13383 10948 bytes
SHA-256: 0912a0b48ac0900f6f4a94df82964468352ca72e514a5493edb5c83966a9af14

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