Malicious PDF — malware analysis report

Static analysis result for SHA-256 758eed5cb8a2aede…

MALICIOUS

PDF

41.4 KB Created: 2020-08-14 07:30:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3f9aeff5f029e9cb4fb6fc8253890498 SHA-1: 85b2706a0e4041dc3c19943dcf477908e34e06e9 SHA-256: 758eed5cb8a2aedefa30060c3cb2887c9004abf7451d63bd3a4494840adf1d31
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm and a redirector to malicious infrastructure, disguised as a reading comprehension workbook. The ML classifier strongly indicated maliciousness, and the embedded URLs point to known malicious redirectors. The document body itself is heavily obfuscated but contains references to the lure URL.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://ttraff.com/wb?keyword=reading%20comprehension%20workbook%20grade%207%20pdf
    • http://files.gochamber.org/uploads/1/3/1/0/131069987/118134.pdf
    • http://womezigad.kazquilting.com/uploads/1/3/0/8/130874254/5860754.pdf
    • http://files.norwalklightning.com/uploads/1/3/1/4/131483110/kixubora.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://cdn.shopify.com/s/files/1/0436/3150/9664/files/behavioural_therapy_techniques.pdf
    • https://cdn.shopify.com/s/files/1/0427/6181/4172/files/agree_ii_tool.pdf
    • https://cdn.shopify.com/s/files/1/0432/5539/8563/files/29179809955.pdf
    • https://cdn.shopify.com/s/files/1/0434/1386/4615/files/61180567276.pdf
    • https://cdn.shopify.com/s/files/1/0430/8838/0061/files/sufofadoxawesupuzobolili.pdf
    • https://cdn.shopify.com/s/files/1/0429/6084/7004/files/44575716605.pdf
    • https://cdn.shopify.com/s/files/1/0434/2074/5893/files/awake_my_soul_chords.pdf
    • https://cdn.shopify.com/s/files/1/0432/8531/5739/files/nigiwazuvipuzanefa.pdf
    • https://cdn.shopify.com/s/files/1/0430/0580/4698/files/11043515311.pdf
    • https://cdn.shopify.com/s/files/1/0429/2201/6934/files/17290227638.pdf
    • https://cdn.shopify.com/s/files/1/0434/9886/4804/files/english_analytical_reasoning_mcqs_with_answers.pdf
    • https://cdn.shopify.com/s/files/1/0429/5029/5708/files/30310566079.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_off00006244.bin
620f69990d612219ac04e197f388330092edb8ec4ff69ffd35a86ff63cbae38c
pdf-font-stream PDF embedded font (sfnt) at offset 0x6244 5920 bytes
font_01_sfnt_off00007657.bin
1647a2a77f094fe602fd6f59d625e8ab5ec3aeb805b4f33aae20ea3973d9c6f3
pdf-font-stream PDF embedded font (sfnt) at offset 0x7657 10140 bytes