Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4cea7a40535e7d5…

MALICIOUS

PDF

76.1 KB Created: 2021-06-20 16:51:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-23
MD5: 766e2f6188fb52b464298e2553c50ec8 SHA-1: ab402674f9a9c159a902b18b63e443f0bb9358db SHA-256: c4cea7a40535e7d5bc5db82aa1d76779411c0c0bc46ca6c75610cd6bf91f239b
164 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://anhuishangbiao.com/upload_fck/file/2021-6-14/20210614142049652353.pdf In PDF document text
    • https://ludbaegitim.com/calisma2/files/uploads/lulenagufixalib.pdfIn PDF document text
    • http://live-lessons.net/lcj/web/uploads/assets/file/12395000065.pdfIn PDF document text
    • http://ccsl.asia/files/kubururo.pdfIn PDF document text
    • http://teaandtiarasottawa.org/clients/e/e8/e8f54e69a7463df9fd0adff13cd8e90f/File/lelikimab.pdfIn PDF document text
    • http://woodwork.pl/ubezpiecz/obrazy/file/lodubig.pdfIn PDF document text
    • http://parejalecaros.com/adjunto/upload/fck/files/55838881134.pdfIn PDF document text
    • https://shinyjewellers.com/wp-content/plugins/super-forms/uploads/php/files/ug695t6m2tvtnskvvkkta8mthv/23932795052.pdfIn PDF document text
    • http://seksdagen.nl/userfiles/file/panivofokiwu.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b0457ca3a0---14065459978.pdfIn PDF document text
    • http://sbhs1967.com/clients/8/89/8985ce50e7417da620f75e2af787291b/File/favitosexovaxepinudid.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16071f40ea0ff1---tatifafiteg.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160948cd96ef2d---8319217345.pdfIn PDF document text
    • https://greyquotient.com/wp-content/plugins/super-forms/uploads/php/files/2792bd06462a58aa5b9d391ea6e00ceb/bafukirilonedupoz.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160703e566f67c---fusiraguwumegum.pdfIn PDF document text
    • https://www.web2business.pt/wp-content/plugins/formcraft/file-upload/server/content/files/1608701b2b98d9---tagunisolotadubifarur.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/b35dmk04f5o0ooiceopvbpovv6/90681818497.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/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=ets+2+download+crackPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e812.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE812 5176 bytes
SHA-256: d678241eca0fd89d5f64d9fd3632d158e3fabfe519a253d338d4c4934f959bba
font_01_sfnt_off0000f9d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9D5 12420 bytes
SHA-256: 122024bc555147a3512c0b77bc77fae65cd0dc56cc02a70aff570639deb08e17