Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a27dc2f8c028515…

MALICIOUS

PDF

73.9 KB Created: 2021-06-11 19:59:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 8d527fae7e051e438875bf65227741a6 SHA-1: 716e8a3b8fa65faaddf68bc271d29f99871167d3 SHA-256: 8a27dc2f8c0285158c01cef8dc134e34092d090e5ef33d29ec6ecec9d590c9e7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains a heuristic firing for a mass external PDF link farm, with one of the primary URLs being `https://medvor.ru/pbw?utm_term=instagram+app+latest+version+apk+download`. This URL, combined with the ClamAV detection of 'Pdf.Phishing.Trojan', strongly suggests a phishing or malware distribution attempt disguised as a legitimate download. The document body, though heavily obfuscated, contains text related to 'Instagram app latest version apk download', reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://medvor.ru/pbw?utm_term=instagram+app+latest+version+apk+download
    • https://cdn-cms.f-static.net/uploads/4403805/normal_5fe78f2398f63.pdf
    • https://cdn-cms.f-static.net/uploads/4410432/normal_604d2111b1e94.pdf
    • https://luzepomi.weebly.com/uploads/1/3/1/8/131856518/kebiwozulakel.pdf
    • https://static.s123-cdn-static.com/uploads/4392656/normal_5fffbe0237db7.pdf
    • https://cdn-cms.f-static.net/uploads/4464065/normal_6022b3891258c.pdf
    • https://cdn-cms.f-static.net/uploads/4470537/normal_606e7144e1c24.pdf
    • https://penonogam.weebly.com/uploads/1/3/4/0/134012545/6264661.pdf
    • https://cdn-cms.f-static.net/uploads/4368752/normal_6033fa9d78faa.pdf
    • https://cdn-cms.f-static.net/uploads/4490961/normal_60689854210b2.pdf
    • https://cdn-cms.f-static.net/uploads/4458421/normal_602c25ac8fa80.pdf
    • https://cdn-cms.f-static.net/uploads/4484834/normal_60421b3f27759.pdf
    • https://tilivugex.weebly.com/uploads/1/3/4/1/134108965/begubemuz.pdf
    • https://cdn-cms.f-static.net/uploads/4460247/normal_6055ffc47a3ae.pdf
    • https://cdn-cms.f-static.net/uploads/4454681/normal_604a895a3d0ce.pdf
    • https://lafakizivubev.weebly.com/uploads/1/3/4/7/134767266/4977193cafa9.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://genarozep.pbworks.com/f/the_ab_real_book_b_flat.pdf
    • http://bupataved.pbworks.com/w/file/fetch/144777645/dividing_fractions_word_problems_6th_grade.pdf
    • http://gezebal.pbworks.com/w/file/fetch/144738273/como_descobrir_a_senha_do_wifi_pelo_celular_-_j_conectado_iphone.pdf
    • http://sozevupegufi.pbworks.com/f/63775524206.pdf
    • http://dufogeruzipu.pbworks.com/f/holly_glover_schreiber_wichita.pdf
    • http://febokipup.pbworks.com/f/xepum.pdf
    • http://munonoraze.pbworks.com/w/file/fetch/144457392/piramide_de_las_necesidades_basicas_de_abraham_maslow.pdf
    • http://pewexojazo.pbworks.com/w/file/fetch/145027110/xhubs_download_apk_pc.pdf
    • http://lekipirunezi.pbworks.com/w/file/fetch/144427926/65432458845.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e318.bin
9de7c3c76e26bf90d7108a90c41ef139a09481a66b80f1d7b5ed7dfe21d74a3c
pdf-font-stream PDF embedded font (sfnt) at offset 0xE318 5432 bytes
font_01_sfnt_off0000f595.bin
973aea7fad6089ddf7b3a04eada8821df3a85d45825042aff3306c7dc381c99a
pdf-font-stream PDF embedded font (sfnt) at offset 0xF595 10568 bytes